Ross Island, Antartica, beneath Mount Erebus, the worlds southernmost active volcano
Name: Mount Erebus was discovered on January 27, 1841 by polar explorer Sir James Clark Ross who named it after his ships, Erebus and Terror. Erebus was a primordial Greek god of darkness, the son of Chaos.
How it was formed: The volcano constantly releases hot gases which steam up through cracks and fractures in the volcanic rocks. As soon as this gas hits the frigid Antarctic air it freezes, and over time has created an intricate network of delicate ice caves and hollow towers, some as tall as 30 feet.
photo by George Steinmetz
http://www.georgesteinmetz.com/section10
my friend kristen is here right now in Waitomo, New Zealand.
The word Waitomo comes from the Māori language wai meaning water and tomo meaning a doline or sinkhole; it can thus be translated as 'water passing through a hole'.
There are around 300 caves in Waitomo, but it's not the geological formations that make these into a subterranean wonderland, it's the larvae of their resident glow worm - Arachnocampa luminosa, a species unique to New Zealand.
Photograph by Carsten Peter/Speleoresearch & Films. Published in National Geographic.
Beneath the town of Naica in the Chihuahuan Desert, Mexico. Geological Features: The cave is also known as Cueva de los Cristales. It contains the largest natural crystals ever found, which are composed of selenite. The largest is 11 m (36 ft) in length, 4 m (13 ft) in diameter and 55 tons in weight.
this cave is Dongzhong cave school, Miao village, Ziyun county, China.
Dongzhong means 'in cave'. The Dongzhong cave was formed by wind and water erosion over thousands of years. Now two hundred pupils, 18 families and their livestock live here.
most info and pictures found here:
http://www.ironammonite.com/2012/01/5-jaw-dropping-caves-supermans-fortress_18.html