Bizarre and unusual destinations around the world
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Moaning Cavern, Vallecito, Calif.( Stephen Osman / Los Angeles Times )
This is one of California's largest caves and drops visitors 272 feet below the earth's surface. No matter the temperature outside, the cave's interior remains 61 degrees. Plus, the cave walls drip with moisture. In fact, the dripping creates the moaning sound that gives the cave its name.
Read more: Exploring Moaning Cavern
-- Hugo Martin
For more info: http://www.caverntours.com