Moidams, the mound-burial system of the Ahom Dynasty, represent a royal cemetery established by the Tai-Ahom people in northeastern India. Located at the foothills of the Patkai Ranges in eastern Assam, the site holds sacred significance for the Tai-Ahom and reflects their unique funerary traditions.

Under the leadership of Prince Siu-Ka-Pha, the Tai-Ahom migrated to present-day Assam in the 13th century and chose Charaideo as their first capital and the site for this royal necropolis. Over 600 years (13th to 19th centuries CE), they constructed Moidams, meaning “home for spirit,” harmonizing with the natural landscape of hills, forests, and water. The sacred geography was further enhanced by planting holy trees and creating water bodies, blending spiritual and natural elements.

Mound-Burial System

The Charaideo necropolis houses 90 Moidams, situated on elevated terrain. These burial mounds, or Ga-Moidams, are constructed by building an earthen mound over a hollow vault (Tak) made of brick, stone, or earth, topped by a shrine at the center of an octagonal wall (Garh), symbolizing the Tai universe. At the summit, the Mungklang shrine represents a golden ladder, symbolizing the connection between heaven and earth.

The vaults enshrine the buried or cremated remains of kings and other royals, accompanied by grave goods such as food, horses, elephants, and occasionally queens and servants. Over time, the Moidams have evolved in materials and design, reflecting changes in the burial traditions of the Tai-Ahom dynasty.

The UNESCO World Heritage List

Moidams, the mound-burial system of the Ahom Dynasty, stand as enduring evidence of 700 years of Tai-Ahom royal funerary architecture and customs, reflecting their cultural traditions from the 13th to 19th centuries CE. The archaeological remains of these Moidams showcase the architectural designs, layouts, and expressions of Tai-Ahom beliefs and traditions.

The 700-year-old Moidams, the Ahom dynasty burial mounds in Assam, were added to the UNESCO World Heritage List in 2024. According to UNESCO, “Moidams are vaulted chambers (chow-chali), often double-storied, with an arched passage for entry. They hold the remains of kings, royals, and grave goods like food. Over time, these mounds become covered in vegetation that resembles small hillocks.

Also Read-  Kaas Pathar: A UNESCO World Heritage Site of Floral Splendor

Structure

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The Kas Plateau, also known as Kaas Pathar, is 25 kilometers west of Satara City in Maharashtra, India. It is part of the Sahyadri Sub-Cluster of the Western Ghats and was designated a UNESCO World Natural Heritage Site in 2012. Renowned as a biodiversity hotspot, the plateau is famous for its seasonal bloom of wildflowers and numerous endemic butterfly species, particularly during August and September. Situated at an altitude of 1,200 meters and covering an area of approximately 10 square kilometers, Kaas is home to over 850 species of flowering plants. These include orchids, shrubs like the Karvy, and carnivorous plants like Drosera indica.

Bhambavli Flower

The Bhambavli Flower Plateau, the largest flower plateau in the world, is located just 3 km from the Kaas Plateau. South of the Kaas Plateau lies the Kaas Lake, surrounded by dense forests and situated between Sajjangad Fort and the Kanher Dam. Approximately 30 km south of Kaas Lake is the Koyna Hydroelectric Project. Additionally, the Bhambavli Vajrai Waterfall, one of India’s tallest waterfalls, is also located nearby. The plateau is situated 20 km from the northern part of Koyna Wildlife Sanctuary, with a significant portion designated as a Reserve Forest. Kaas Lake, constructed over a century ago, serves as a perennial water source for the western part of Satara city, supplying water through a gravity-based system.

Geology

The plateau, formed from volcanic basalt, lies within the biosphere of the Western Ghats. Its unique flora, largely restricted to this locality, thrives on the thin layer of soil—no more than 25 millimeters thick—formed from the weathering of exposed basalt rock. The Kaas Plateau, located near Satara, is a high-altitude plateau and grassland that transforms into a vibrant “valley of flowers” during the monsoon season, particularly between August and early October. The plateau is home to over 150 species of flowers, shrubs, and grasses, with orchids blooming for a brief period of 3–4 weeks. Recognized as a UNESCO World Natural Heritage Site, it is part of the Sahyadri Sub-cluster of the Western Ghats.

Kaas Pathar weather

The weather at Kaas Pathar (Kaas Plateau) varies significantly across the seasons due to its high-altitude location and exposure to seasonal climatic conditions-

Monsoon (June to September):

Monsoon is the peak season for visitors as the plateau transforms into a “valley of flowers.” The area experiences heavy rainfall, with lush greenery and vibrant wildflowers in full bloom. The weather is cool, wet, and misty, ideal for nature enthusiasts. Temperature: 20°C to 25°C.

Post-Monsoon (October to November):

The flowers begin to fade, but the weather remains pleasant with clear skies and mild temperatures. It’s a good time for trekking and enjoying the scenic beauty without the heavy crowds. Temperature: 18°C to 25°C.

Winter (December to February):

Winters are dry and cold. The plateau becomes less colorful, and the grasslands dry out. The weather is chilly, especially during early mornings and nights. Temperature: 5°C to 15°C.

Summer (March to May):

Summers are hot and dry, with temperatures sometimes soaring above 40°C. The plateau becomes barren, with minimal vegetation. This season is less favorable for visits due to the heat. Temperature: 30°C to 40°C.

Best time to visit kaas pathar

The ideal time to visit Kaas Pathar is during the monsoon and post-monsoon seasons (August to early October) when the flowers are in full bloom and the weather is most pleasant.

Places to visit near Kaas Pathar

Kaas Pathar (Kaas Plateau) is surrounded by several attractions, making it a great destination for nature lovers, adventure seekers, and history enthusiasts. Here are some notable places to visit near Kaas Pathar.

Kaas Lake

Located just south of the Kaas Plateau, this serene lake is surrounded by dense forests and offers picturesque views. It’s an excellent spot for a peaceful retreat.

Bhambavli Vajrai Waterfall

Known as one of the tallest waterfalls in India, this stunning three-tiered waterfall is located near Bhambavli village, around 5-6 km from Kaas Plateau. It’s a must-visit for nature enthusiasts.

Sajjangad Fort

This historic fort was the final resting place of the saint Samarth Ramdas. It offers panoramic views of the surrounding region and is a popular pilgrimage site. Distance is 20 km from Kaas.

Koyna Wildlife Sanctuary

A UNESCO World Heritage Site, this sanctuary is part of the Western Ghats and offers a chance to spot diverse flora and fauna. It’s ideal for trekking and wildlife photography. Distance is nearly 20 km from Kaas.

Also Read- The Chota Nagpur Plateau: A Geological and Cultural Treasure

How to Reach Kaas Pathar

Reaching Kaas Pathar (Kaas Plateau) is relatively straightforward as it is well-connected by road and lies near the city of Satara in Maharashtra. Here’s how you can reach the plateau:

The nearest airport is Pune International Airport, located approximately 140 km from Kaas Pathar. From the airport, you can hire a taxi or take a bus to Satara, and then proceed to Kaas Plateau. The nearest railway station is Satara Railway Station, about 25 km from Kaas Pathar. It is well-connected to major cities like Pune, Mumbai, and Kolhapur.

You can drive or hire a taxi to Kaas Plateau via the Satara-Kaas Road. It is a scenic drive and takes about 45 minutes. If you drive from Mumbai,
Drive via NH48 (Mumbai-Bangalore Highway) to Satara, then follow the Satara-Kaas Road. The journey takes around 3-4 hours.

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The Chota Nagpur Plateau, located in eastern India, spans much of Jharkhand and extends into neighboring regions of Chhattisgarh, Odisha, West Bengal, and Bihar. Bordered by the Indo-Gangetic Plain to the north and east and the Mahanadi River basin to the south, the plateau covers an area of approximately 65,000 square kilometers. Chota Nagpur Plateau is probably the world’s largest collection of megaliths, spread over 53 known sites.

Geology

The Chota Nagpur Plateau is a continental plateau, characterized by an extensive landmass uplifted above the surrounding terrain. Composed of Precambrian rocks over 540 million years old, the plateau was shaped during the Cenozoic era through tectonic-driven continental uplift. Its ancient origins are evidenced by Gondwana substrates, linking it to the Deccan Plate, which separated from the southern supercontinent during the Cretaceous period. This plate embarked on a 50-million-year drift before colliding with the Eurasian continent, with the northeastern Deccan Plateau, including this ecoregion, marking the initial point of contact. The region’s geological history features prolonged episodes of metamorphism, granitic activity, and igneous intrusions spanning from over 1,000 million years ago to about 185 million years ago.

Division

The Chota Nagpur Plateau is divided into three distinct steps. The highest step is located in the western part of the plateau, where local plateaus, known as pats, rise to elevations of 910 to 1,070 meters above sea level, with the highest point reaching 1,164 meters. The middle step includes much of the old Ranchi and Hazaribagh districts, as well as parts of the former Palamu district before it was divided into smaller administrative units. The average elevation in this region is around 610 meters, and the topography is undulating, with prominent gneissic hills, often dome-shaped. The lowest step, at about 300 meters, covers the former Manbhum and Singhbhum districts. This section features high hills, such as Parasnath Hills, which rise to 1,370 meters, and Dalma Hills, reaching 1,038 meters. The large plateau is further subdivided into several smaller plateaus or sub-plateaus.

Chota Nagpur Plateau in India Map

Chota Nagpur, the plateau in eastern India, in northwestern Chhattisgarh and central Jharkhand states. The plateau is composed of Precambrian rocks.

Chota Nagpur Plateau Weather

Highest Peak of Chota Nagpur Plateau

Mineral Resources

The Chota Nagpur Plateau is a rich repository of mineral resources, including mica, bauxite, copper, limestone, iron ore, and coal. The Damodar Valley, in particular, is known for its abundant coal reserves and is regarded as the primary center for coking coal in India. Extensive coal deposits are located in the central basin, covering an area of 2,883 square kilometers (1,113 square miles). Key coalfields in the region include Jharia, Raniganj, West Bokaro, East Bokaro, Ramgarh, South Karanpura, and North Karanpura.

Fossil record

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The remote village of Malana, nestled in the pristine Parvati Valley of Himachal Pradesh, is a destination steeped in mystery and enchantment. Renowned for its unique customs, ancient traditions, and stunning natural beauty, Malana has long fascinated travelers seeking a glimpse into its distinctive way of life. This article explores the allure of Malana, a village that has preserved its rich cultural heritage and remains a hidden gem in the Himalayas.

History

Malana is often regarded as one of the world’s oldest democracies, boasting its unique laws, traditions, and governance system. The residents, known as Malanis, revere their deity, Jamlu, who is the village’s protector. These time-honored customs and practices, preserved over centuries, make Malana a captivating destination for history enthusiasts.

The Malanis communicate in Kanashi, a unique language that sets them apart from the communities in the surrounding regions. Their attire, culture, and social practices are deeply intertwined with their traditional belief systems. Visitors are advised to respect local customs, including refraining from touching the villagers or their belongings, as such actions are believed to bring misfortune to the community.

Natural beauty

Malana is enveloped by verdant forests, with majestic snow-capped peaks creating a breathtaking backdrop. The tranquil Malana River enhances the village’s charm, offering a serene atmosphere that captivates trekkers and nature lovers alike. For adventure enthusiasts, treks to nearby destinations such as Chandrakhani Pass and Deo Tibba are among the most popular activities, promising unforgettable experiences in the heart of nature.

Malana Valley Trek

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The centerpiece of the Ngorongoro Conservation Area is the Ngorongoro Crater, the world’s largest inactive, intact, and unfilled volcanic caldera. Formed two to three million years ago when a massive volcano erupted and collapsed on itself, the crater is approximately 610 meters deep, with a floor spanning 260 square kilometers. Estimates suggest that the original volcano stood between 4,500 and 5,800 meters tall. Today, the crater floor lies at an elevation of 1,800 meters above sea level.

The Ngorongoro volcano was active between 2.45 and 2 million years ago, and similar volcanic collapses created the smaller calderas of Olmoti and Empakaai. The Munge Stream flows northward from the Olmoti Crater and serves as the primary water source for the seasonal salt lake at the center of the Ngorongoro Crater. This lake is known by two names: Makat, meaning “salt” in Maasai, and Magadi. The Lerai Stream, originating from the humid forests south of the crater, sustains the Lerai Forest on the crater floor.

Ngorongoro Crater Map

The Ngorongoro Crater map shows a great land area not only Ngorongoro Crater but all of Ngorongoro Crater conservation area and all its unique attraction points.

Ngorongoro Crater Weather

Geology

The Pliocene Ngorongoro volcanic group comprises eight extinct shield volcanoes located within the Eyasi half-graben, bordered to the east by the Gregory Rift’s Western Escarpment and to the southwest by the Lake Eyasi escarpment. Among these volcanoes, five are dome-shaped cones, while three feature calderas. Ngorongoro Volcano (2.5–1.9 million years ago) is primarily composed of basaltic trachyandesite. The caldera is sustained by the Munge and Oljoro Nyuki Rivers, with the Ngoitokitok hot springs feeding the Goringop swamp. Lake Magadi, a shallow alkaline lake with a depth of 1.7 meters, also lies within this system.

Other volcanoes in the complex include Olmoti (2.01–1.79 million years ago), Empakaai, Loolmalasin, Sadiman (3.7 million years ago), Lemagrut, and Oldeani. The northwest section of the conservation area encompasses the Serengeti Plains, Salei Plains, Oldupai Gorge, and the Gol Mountains inselbergs. These inselbergs are quartzite and mica schist formations from the Mozambique Belt, dating back approximately 800–500 million years.

The Ngorongoro Conservation Area

The Ngorongoro Conservation Area encompasses vast highland plains, savannas, woodlands, and forests. Established in 1959 as a multiple-use area, it allows wildlife to coexist with semi-nomadic Maasai pastoralists who practice traditional livestock grazing. At its heart lies the breathtaking Ngorongoro Crater, the world’s largest caldera. This area holds global significance for biodiversity conservation, hosting numerous threatened species, and a high density of wildlife, and serving as a key route for the annual migration of wildebeest, zebras, gazelles, and other animals across the northern plains. Additionally, extensive archaeological discoveries within the area provide a rich record of human evolution and interactions with the environment, including early hominid footprints dating back 3.6 million years.

Oldupai or Olduvai Gorge

Ngorongoro Crater National Park

The Ngorongoro Crater is not a national park but a part of the Ngorongoro Conservation Area (NCA) in northern Tanzania, a UNESCO World Heritage Site. The NCA was established in 1959 as a multiple-use area, where wildlife conservation, archaeological heritage, and the traditional practices of the Maasai people coexist.

Unlike national parks such as Serengeti, the Ngorongoro Conservation Area allows for multiple uses, including wildlife conservation and Maasai livestock grazing. It is managed by the Ngorongoro Conservation Area Authority (NCAA), not the Tanzania National Parks Authority (TANAPA).

Sanctuary Ngorongoro Crater camp

Sanctuary Ngorongoro Crater Camp is a luxury safari accommodation located near the Ngorongoro Crater rim, offering an exceptional base for exploring this UNESCO World Heritage Site. The camp combines comfort with immersive wildlife experiences, making it a popular choice for travelers seeking a premium yet intimate safari adventure.

Ngorongoro Crater Safari

A safari in the Ngorongoro Crater is one of Africa’s most iconic wildlife experiences, offering incredible scenery, rich biodiversity, and unparalleled opportunities to observe animals in their natural habitat.

Wildlife Abundance: The crater is home to about 25,000 large animals, including the Big Five (lion, leopard, elephant, buffalo, and rhino). It is one of the best places in Africa to spot the rare black rhinoceros.

Diverse Ecosystems: The crater floor includes grasslands, swamps, forests, and a salt lake (Lake Magadi), creating a habitat for various species. Scenic Beauty: As the world’s largest unbroken caldera, the Ngorongoro Crater offers breathtaking panoramic views from its rim.

Highlights of a Safari

Game Drives: Safaris typically start early in the morning for the best wildlife sightings. Open safari vehicles with experienced guides provide optimal viewing. The crater floor is ideal for observing predators, herbivores, and birdlife.

Bird Watching: Over 500 bird species can be found, including flamingos on Lake Magadi, crowned cranes, and secretary birds. Best during the wet season when migratory birds arrive.

Cultural Interaction: Visit nearby Maasai villages to learn about traditional culture and lifestyle. The Maasai are integral to the Ngorongoro ecosystem, with historical coexistence alongside wildlife. Picnic Sites: Enjoy packed meals at designated spots like Ngoitokitok Springs, surrounded by hippos and beautiful scenery.

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The Dune of Pilat, also known as Grande Dune du Pilat, is the tallest in Europe. Situated in La Teste-de-Buch near the Arcachon Bay area in France, it lies approximately 60 km southwest of Bordeaux along the Atlantic coastline. The Dune of Pilat is a renowned tourist attraction with over two million visitors annually. Formed over 4,000 years ago on the site of ancient protohistoric camps, the Dune of Pilat now attracts nearly two million visitors annually, making it one of France’s most popular natural sites, second only to the Calanques of Cassis. Spanning almost three kilometers, its exposed location along the sea and steep slopes create ideal conditions for paragliding, drawing enthusiasts from around the world.

Since 1922, numerous archaeological discoveries have been made at the dune. In 2013, a tourist found a funeral urn and accessory vase from the Iron Age, dating back to approximately 800 BC, at its base. The Dune of Pilat has an estimated volume of around 60 million cubic meters, spanning approximately 500 meters in width from east to west and extending 2.7 kilometers in length from north to south, covering an area of 1.35 square kilometers. In 2018, its height was recorded at 106.60 meters above sea level.

The Dune of Pilat-History

As a foredune, it runs parallel to the shoreline just behind the beach’s high tide line. Over time, the dune has gradually moved landward, encroaching on the forest and covering structures, roads, and parts of the Atlantic Wall. Historical maps from 1708 and 1786 show areas named Pilat south and offshore of the dune’s current position, indicating this coastal shift. Until the 1930s, the current site was known as “Les Sabloneys,” or “The New Sands,” before it was renamed the Dune of Pilat by real estate developer Daniel Meller. The name Pilat derives from the Gascon word Pilhar, meaning heap or mound.

On January 24, 2009, a storm hit the Dune of Pilat, with peak winds reaching 175 km/h, causing damage to the dune. The area now occupied by the Dune of Pilat once hosted temporary protohistoric camps used for sea salt mining. Archaeological exploration began in 1922, and on December 31, 2013, a tourist discovered a funeral urn and an accessory vase dating back to the Iron Age (around 800 BC) in the sand at the base of the dune. In October 2014, a team of about ten amateur archaeologists conducted a two-week excavation to better understand the stratigraphy and environmental context of these findings.

Also Read- Eruptions and Mysteries of Old Faithful Geyser

Camping at the Dune

This area offers plenty of camping options, with golden sandy beaches and stunning blue waters close by—not to mention the iconic dune itself. Load up the car with all your seaside essentials and prepare for a relaxing coastal getaway. Pyla Camping provides a wide range of accommodations for your stay near the dune. Relax by the pool, enjoy the beach, and let the kids have fun at the children’s club.

How to Reach Dune of Pilat

By Car:  From Bordeaux: Take the A63 and A660 highways toward Arcachon. The trip is around 60 km and takes approximately 1 hour. Follow signs for “Dune du Pilat” or “La Teste-de-Buch.” By Train: From Bordeaux: Take a TER (regional train) from Bordeaux Saint-Jean Station to Arcachon Station (about a 50-minute journey). From Arcachon, you can take a bus or taxi to reach the dune.

By Bus: From Arcachon: Take the Baïa Bus (Line 1) from Arcachon Station toward Plage de la Salie, which stops near the Dune of Pilat.  In peak tourist seasons, shuttle services often run directly from Arcachon to the dune.

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Old Faithful is one of the most famous geysers in the world, located in Yellowstone National Park in Wyoming, USA. Named for its remarkably consistent eruptions, Old Faithful has captivated visitors for over a century. It erupts roughly every 90 minutes, shooting hot water and steam anywhere from 100 to 180 feet into the air. The duration and frequency of each eruption can vary slightly, but its predictability has earned it a special place among Yellowstone’s geothermal features.

Old Faithful is one of nearly 500 geysers in Yellowstone. Predicting geyser eruptions with regularity is rare, yet Old Faithful has lived up to its name, with its eruption intervals only lengthening by about 30 minutes over the past 30 years. Thermal features in Yellowstone are constantly changing, and it’s possible that Old Faithful may eventually stop erupting. Geysers and other thermal features reflect ongoing volcanic activity below the surface, and change is an inherent part of this natural system. Yellowstone preserves these geological processes, allowing visitors to experience and appreciate this dynamic landscape.

The water in Old Faithful is heated by the geothermal activity below, reaching up to 96°C. Each eruption releases thousands of gallons of water, creating a spectacular display that lasts from 1.5 to 5 minutes. Park rangers and scientists closely monitor the cycle between eruptions, using data from past eruptions to make fairly accurate predictions for visitors. Yellowstone itself sits atop a volcanic hotspot, which fuels the park’s extensive geothermal activity, including hot springs, mud pots, fumaroles, and geysers like Old Faithful.

Geology

The Greater Yellowstone Ecosystem’s landscape is the result of diverse geological processes over the past 150 million years. Over this time, Earth’s crust has been compressed, stretched, glaciated, eroded, and shaped by volcanic activity. These powerful forces have formed the mountains, canyons, and plateaus that make Yellowstone National Park a natural marvel.

Although these mountains and canyons may seem unchanged over a human lifetime, they remain incredibly dynamic and active. Yellowstone is home to some of Earth’s most active volcanic, hydrothermal (water + heat), and earthquake systems, making it an invaluable natural treasure. Yellowstone was designated the world’s first national park primarily due to its remarkable geysers, hot springs, mud pots, and steam vents, along with other wonders like the Grand Canyon of the Yellowstone River.

Also Read- The Last of the Giants: A Look at California’s Redwood Trees

The hills around Old Faithful and the Upper Geyser Basin are reminders of rhyolitic lava flows from the Quaternary period. These flows, which occurred long after the massive eruption 600,000 years ago, spread across the landscape like stiff mounds of bread dough due to their high silica content. Evidence of glacial activity is widespread here and plays a crucial role in the existence of geysers. Glacial till deposits beneath the geyser basins act as natural storage reservoirs for eruption water. Many features, like the Porcupine Hills north of Fountain Flats, are made up of glacial gravel, serving as reminders that this region was covered by ice as recently as 13,000 years ago.

Signs of erosion are visible throughout the area, from runoff channels etched into the geyser basins’ sinter deposits to the drainage system created by the Firehole River. Evidence of mountain building also appears as you travel south of Old Faithful toward Craig Pass, where the Rocky Mountains rise to 2,518 m, dividing the region into two separate watersheds.

Old Faithful isn’t the tallest or largest geyser in the park; those titles go to the more unpredictable Steamboat Geyser. Old Faithful’s reliability comes from the fact that it’s not connected to any other thermal features in the Upper Geyser Basin.

Upper Geyser Basin

Yellowstone holds nearly 60 percent of the world’s geysers, with the Upper Geyser Basin containing the highest concentration of these delicate features in the park. In this one-square-mile area, there are at least 150 hydrothermal marvels. Out of this impressive number, only five major geysers—Castle, Grand, Daisy, Riverside, and Old Faithful—are regularly predicted by the park’s naturalists. Visitors can also enjoy many frequent, smaller geysers along with numerous hot springs and a recently formed mudpot within this basin.

How Often Does Old Faithful Erupt

Old Faithful erupts roughly every 90 minutes, though intervals can range from about 60 to 110 minutes. Each eruption typically lasts between 1.5 and 5 minutes, with water and steam reaching heights of 100 to 180 feet. The frequency of eruptions can vary due to changes in geothermal activity, and park rangers use past data to predict each eruption time within a window of about 10 minutes. This predictability is rare among geysers, making Old Faithful one of Yellowstone’s most popular attractions.

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California’s giant redwoods, also known as coast redwoods (Sequoia sempervirens), are among the tallest trees on Earth, reaching heights of over 107 meters and living for up to 2,000 years. Giant redwood trees commonly known as the giant sequoia, giant redwood, Sierra redwood, or Wellingtonia, is a coniferous tree in the Cupressaceae family, within the Sequoioideae subfamily. Native to groves on the western slopes of California’s Sierra Nevada mountains, where consistent moisture, mild temperatures, and nutrient-rich soils foster their growth.

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The ground in Mexico City is sinking at a rate of nearly 50 centimeters (20 inches) per year, and this subsidence is expected to continue without any recovery, according to a new study by Chaussard et al. Using 115 years of ground-based data and 24 years of satellite measurements, a team of U.S. and Mexican scientists has determined that large areas beneath Mexico City are steadily compacting after having been drained of water long ago. They predict that this compaction will continue for about 150 years, potentially adding up to 30 meters of subsidence on top of the several meters already recorded during the 20th century.

Unlike subsidence in many other cities, Mexico City’s sinking isn’t closely linked to current local groundwater pumping rates. Instead, it is due to the gradual compaction of the ancient lake bed on which the city is built. This lake bed was once Lake Texcoco, the site of the Aztec city Tenochtitlán. As water extraction pushed groundwater deeper underground, the 100-meter-thick, salty, clay-rich lake bed dried out. The fine mineral particles in the soil have been gradually compressing, leading to ongoing ground subsidence.

This type of compaction is irreversible, the researchers note, and it is causing widespread fractures that damage buildings, historical sites, sewers, and gas and water lines throughout the city. These fractures are also allowing contaminated surface water to seep into the ground, which could further complicate access to clean water in a city where it is already a challenge.

History

Densely populated Mexico City sprawls across a high-altitude lake bed, roughly 7,300 feet above sea level. Built on clay-rich soil that is now causing the city to sink, Mexico City is also highly susceptible to earthquakes and vulnerable to the impacts of climate change. Today, it is likely one of the last places anyone would consider building a megacity.

The Aztecs chose this location to build their city of Tenochtitlan in 1325. when it was a collection of lakes. They established the city on an island and expanded it outward, creating a network of canals and bridges that integrated with the surrounding water.

Also read- Why The Pacific Ocean Is Shrinking and The Atlantic Ocean Is Widening

However, when the Spanish arrived in the early 16th century, they dismantled much of the Aztec city, drained the lakebed, filled in the canals, and removed the forests. They viewed water as “an enemy to overcome for the city to thrive,” explained Jose Alfredo Ramirez, an architect and co-director of Groundlab, a design and policy research organization.

Subsidence Leading to extensive damage

Many cities have experienced subsidence, but Mexico City’s situation is extreme. Venice, for example, sank about 9 inches over the 20th century due to a drop in its water table. In contrast, Mexico City has sunk 30 feet.

The subsidence has not been uniform, leading to extensive damage over the years, especially in the colonial-era city center. In response to severe cracking and the threat of further damage, scaffolding has been erected to support the walls and ceiling of the National Cathedral, the largest and oldest in Latin America, while a costly and complex effort is underway to stabilize its foundations. Across the Zocalo plaza, the National Palace has begun to tilt dangerously, with architects working to keep one wing attached to the rest of the building.

Visible evidence of this sinking can be seen along Line 2 of the city’s Metro. This subway line, which runs above ground along Tlalpan Avenue south of the city center, was perfectly level when it was built in the mid-1960s. Now, the tracks resemble a roller coaster. After subsidence damaged hundreds of irreplaceable colonial churches and mansions, the city halted water pumping in the city center and began drawing water from wells on the outskirts. This change has slowed the sinking in the city center to about an inch per year. However, some suburbs, which rely heavily on wells, continue to sink 18 to 24 inches annually.

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