World’s Deepest Sinkhole: How Huge Are These Topographic Depressions?

A hole in the ground can be both impressive and dangerous. Also known as sinkholes, these topographic depressions are formed when the rocks beneath the surface of the Earth are dissolved by groundwater. Here are five of the deepest sinkholes ever discovered:

1. Xiaozhai Tiankeng, China

The title for being the world's deepest and largest sinkhole is held by Xiaozhai Tiankeng located in Fengjie County in China. It measures 660 meters deep with a volume of 130 million cubic meters.

Tiankeng literally means "The Heavenly Pit" and was formed over the limestone Difeng cave. Carved out by an underground river, this sinkhole is home to a thriving ecosystem of 1,285 species of plants and animals.

For centuries, the local residents have known about the presence of Xiaozhai Tiankeng. It was only discovered by the outside world in 1994 when a group of British explorers tried to study its maze-like underground cave system

2. Taam Ja' Blue Hole, Mexico

In a bay off the shore of the Yucatan Peninsula lies the second-largest blue hole in the world. Taam ja', which means "deep water' in Mayan, was discovered in 2021 although details about this formation just emerged this year.

The giant underwater cave measures 274 meters deep and has sides that are sloping up to 80 degrees. Due to its depth, this geological feature is known for having darker coloration compared to the surrounding surface.

The Taam Ja' blue hole is not an ideal environment to support aquatic life because the water circulation here is not good. However, it is not totally lifeless since it still serves as home to some species of bacteria.

3. Bayou Corne, Louisiana

The Bayou Corne sinkhole in Assumption Parish in Louisiana was discovered two years ago when unexplained seismic activities were reported in the area for several months. Its formation resulted from the collapse of an underground salt dome cave which is connected to an adjacent industrial well.

More than a year after its discovery, the Bayou Corne sinkhole measures about 25 acres and is still growing. As of 2014, it was reported to be at least 229 meters deep.

4. Qattara Depression, Egypt

This sinkhole took thousands of years to form as a result of weathering and wind erosion. It is the second lowest point in the African continent, following Lake Assal in Djibouti. The sinkhole is located in the Matruh Governate in the Western Desert of Egypt. The Qattara Depression covers 19,400 square kilometers of lowland area.

5. Hole of Macaws, Brazil

The Hole of Macaws or Buraco das Araras is considered to be one of the largest sinkholes in the South America. It got its name from the huge number of birds thriving in this area as the depression serves as the breeding ground for the scarlet macaw (Ara macao)

This formation is also categorized as a quartzitic cave which was formed from eroded limestone rocks beneath the surface of the ground. It measures 100 meters deep and has a circumference of 500 meters.