More Planet Earth

I just watched the caves episode and it was absolutely amazing. It really made me want to do some spelunking. I've been fascinated by caves for as long as I can remember, particularly ones with lots of stalactites and stalagmites. Caves such as the one at the beginning of the episode with a 100 meter tall pile of bat guano covered by cockroaches are somewhat less appealing.

I've been lucky enough to visit Carlsbad Caverns, which were breath taking, as well as Mammoth Caves, the longest cave system in the world. But the BBC was able to find some even more incredible caves.

There was a cave in Mexico with a river of sulfuric acid coursing through it, and the air inside is toxic to breath, requiring oxygen masks to explore. Amazingly enough, this inhospitable cave was teaming with fish and other small animals.

Even more fascinating was the cave in, if memory serves me correctly, Australia filled with bioluminescent glow worms. Some of the rooms had so many glow worms on the ceiling that you would swear you were outside looking at a star filled sky. And what's more, they would create strands of silk covered in a glistening, sticky substance to catch insects. It looked like hundreds of strands of pearls dangling from the ceiling.

But by far the most incredible cave was Lechuguilla. Not even discovered until the late 1980's, it still has not been fully explored. Currently it is know to have over 120 miles of caves. What makes this cave so unique, however is that the walls are covered with crystalline formations. Believed to have been carved from sulphuric acid released from the subterranean oil reserves as opposed to the water erosion of most caves, the result is a unique structure and formations. It really is magnificent.

Finally, the word of the day to help you all expand your vocabulary is troglobite. Troglobites are animals adapted to live in the total darkness and inhospitable atmosphere of caves. Free praise goes to the person who can best use it in a sentence.