Infoplease - Did You Know? 'Did You Know?' from the Editors of Infoplease http://www.infoplease.com/daily en-us Copyright 2013 Pearson Education editor@infoplease.com webmaster@infoplease.com Thu, 23 May 2013 04:05:00 GMT Infoplease - Did You Know? http://img.infoplease.com/images/04ip_logo113x20.gif 113 20 http://www.infoplease.com/daily The Mammoth Cave in Kentucky is the longest cave in the world, with 345 miles of subterranean passageways. http://www.infoplease.com/ipa/A0001787.html http://www.infoplease.com/ipa/A0001787.html