Dragon Hole

Dragon Hole with expedition vessels

World’s deepest known undersea sinkhole, 300.89 m deep.

Sima Humboldt and Sima Martel

Sima Humboldt and Sima Martel, sinkholes in Venezuela

314 and 248 meters deep, ancient quartzite sinkholes located on the top of forested table-top mountains and containing patches of isolated, primeval rainforest on their bottoms.

Teiq sinkhole and cave

1.25 km long, 1 km wide, and 250 m deep sinkhole with abrupt walls, volume 90 million m³ – the largest sinkhole by volume in the world. Two perennial streams enter the sinkhole and both disappear underground. Contains also a largely unexplored cave.

Xiaozhai tiankeng

World's deepest sinkhole - Xiaozhai tiankeng, with tourist route visible

Largest sinkhole (tiankeng) in the world, up to 662 meters deep, 625×535 meters across.

Minyé sinkhole and cave

Crossection of Minyé sinkhole, compared with Boeing 747-400, Papua New Guinea

One of the largest and most impressive tiankengs (giant sinkholes) in the world, located in an exotic jungle and crossed by a powerful underground river. Up to 510 meters deep, 350 meters across, volume – 26 million m³. It continues as a cave system. The explored length of cave passages is 5,421 m, maximum depth – 468 m. Contains one of the largest cave rooms in the world – Tuké room, 240 m long, 200 m wide and 130 m high.

Great Blue Hole

Great Blue Hole, Belize

A perfectly round undersea sinkhole, 318 meters across and 124 meters deep. Contains tilted stalactites possibly hinting at tectonic movements.

Crveno Jezero – Red Lake

Crveno Jezero sinkhole, lake

One of the most impressive sinkholes in the world: deep shaft with a lake at the bottom. The total depth of the sinkhole is some 530 m, it contains a 280 – 290 m deep lake with endemic fish.

Sotano de las Golondrinas – Cave of the Swallows

Caver rappelling down into the Sótano de las Golondrinas, Mexico

The largest cave shaft in the world – enormous 49 x 62 meters wide hole, 372 meters deep. Famous due to a group of green parrots who have to fly ascending in circles around the cave until they get out of it.

Black Hole of Andros

Cross section of South Andros Black Hole in south-north direction, compared with Boeing 747-400

300 m wide and up to 47 m deep round water filled sinkhole with a layer of violet jelly layer of bacteria at 18 meters depth. Microorganisms have heated up the water to 40°C.

El Zacaton sinkhole

El Zacaton and Nacimiento spring

The second deepest water-filled sinkhole in the world. The total depth of the sinkhole is 339 m, the lake is 319 m deep. On the surface of the lake, there are floating several round travertine islands. Lake is formed by volcanically heated acidic groundwater.