In thisAug. 16, 2012 photo, a mammoth tusk protrudes from the wall at the U.S. Army Corp of Engineers Cold Regions Research and Engineering Laboratory's Permafrost Tunnel off of the Steese Highway just south of Fox, Alaska in preparation for this weekend's open house at the site. (AP Photo/Fairbanks Daily News-Miner, Eric Engman) MAGS OUT
