FILE - In this July 7, 1956 file photo, Anton Spinas, leader of Swiss climbers, top, tests ropes strung across steep chasm where wreckage of United Airlines UAL DC-7 lays strewn in Grand Canyon. On Tuesday, July 8, 2014, the Grand Canyon National Park will mark the designation of the crash site as a National Historic Landmark in a ceremony overlooking the gorge where the wreckage was scattered over 1.5 square miles. (AP Photo/Pool, File)