In 1991, a Vietnamese farmer found a cave deep in the jungle. It was named Son Doong, meaning "Mountain River Cave." Though it was discovered in 1991, it wouldn't be until 2009 that British experts would explore the cave. What they found there was amazing.
Son Doong is situated in the Phon Nha Ke Bang national park, about 280 miles south of Hanoi. The cave is 87 miles long and contains its own environment - animal life, trees, lakes, beaches, and a river. The cave also happens to be rich in rare pearls that have been shaped by water drops for centuries.