A roof collapse long ago in Hang Son Doong ... An enormous shaft of sunlight plunges into the cave like a waterfall. The hole in the ceiling through which the light cascades is unbelievably ...

For a short period each year - around two weeks in March - the area 200m (656ft) below ground is illuminated by sunbeams that come through a hole in the cave roof and allows some vegetation to grow.

Beneath the land surface of the Bahamas, the underwater caves known as blue holes stretch for hundreds of miles in all directions. Today, these labyrinthine passages host a variety of tiny sea ...

For just a few weeks a year, sunbeams shine two hundred metres down through a hole in the cave roof, illumining the underground world. Filming this natural lightshow successfully relied on it ...

On Dec. 2, 1972, a geological phenomenon occurred in Shelby County. A massive sinkhole opened up in Calera, it's known as the ...

Waterfalls roughly 400 feet high pour through the roof of Deer Cave ... Mulu’s mountains. Other caves, at lower elevations, were like giant storm drains—massive holes in the bedrock that ...