Pictured here are Conrad Anker, left, and Leo Houlding, as they follow in George Mallory's footsteps decked out in replica 1920s-era climbing gear. "It’s phenomenal that they were able to get to 28,000 feet [8,530 meters] in what I would basically call clothing you’d wear to walk through the forest," Anker says. The 1920s leather and hobnail boots, in particular, provided far less warmth than modern climbing boots do.