Open Ceiling Cave

Collapsed sea cave – a circular sea basin that is connected to the sea with a large cave – natural arch that is some 13 m wide. Sea waves enter this cave. In the middle of this basin stands small island – remnants of the fallen cave ceiling.

Maingon Blowhole

Some 40 m deep, narrow sinkhole – a collapse of a sea cave. It is dangerous to attempt to see its bottom but the waves can be heard from it.

Port Campbell Blowhole

Port Campbell Blowhole

A sinkhole – collapse in the roof of sea cave in the spectacular Loch Ard. It is possible that for a while here existed a blowhole with fountain but currently this is a sinkhole with raging sea-water seen in it. This blowhole is loud.

Jacks Blowhole

Jack's Blowhole in New Zealand

Spectacular sinkhole – a large opening in the ground that formed after the sea cave collapse. The sinkhole is some 55 m deep and some 200 m from the sea. It is filled with roaring, raving waves.

Little Salt Spring

Little Salt Spring

Water filled, 61 m deep sinkhole. At the depth of 3 m, the water becomes anoxic. Thanks to this in the sinkhole – spring have been preserved numerous examples of prehistoric fauna and remnants of Palaeo-Indians: hundreds of burials from 4,800 – 3,200 BC.

Lake Jackson

Lake Jackson has gone underground. Porter Sink, June 19, 2012

Shallow, 12 km long lake with two sinkholes in it. This lake has disappeared underground four times since 1907.

Falling Waters Sink

Falling Waters Sink

35 m deep and 6.5 m wide sinkhole. In wet season a stream falls in the sinkhole forming a 22 m high waterfall – the highest in Florida.

Devil’s Den in Florida

Inside the Devil's Den, Florida

A karst window: here through a narrow opening opens a view of a large subterranean river. Here were found remains of animals and traces of prehistoric human activities.

Baboquivari Cave

Sacred cave of Tohono O’Odham people, center of their cosmology. According to their beliefs here lives I’itoi – protector of the people. Nearby are petroglyphs.