In this Dec. 18, 2010 photo, a visitor stops to look at the formations in the Big Room at Carlsbad Caverns National Park near Carlsbad, N.M. Adventurous visitors can opt for several "off-trail" tours ... more 
In this Dec. 18, 2010 photo, a visitor stops to look at the formations in the Big Room at Carlsbad Caverns National Park near Carlsbad, N.M. Adventurous visitors can opt for several "off-trail" tours guided by park rangers through narrow passage ways, across slick flow stone and down ropes and ladders. less 
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Associated Press | Photo By Susan Montoya Bryan
Wed, Jan 5, 2011 3:04 PM EST