The history of mountaineering began on Denali with the legendary story of four gold miners (called "Sourdoughs" because they carried sourdough starter with them at all times) who claimed to have summited after climbing more than 8,000 feet of steep snow and ice, then back down again—all in a single and incredibly dangerous day in 1910. Lugging a 25-pound, 14-foot flagpole to mark their success, they took on North America's highest peak using sheet metal crampons, coal shovels, hatchets, and alpenstocks to balance their way up the mountain. Was the expedition a success or a hoax? Denali climber Jon Waterman brings this colorful mountaineering mystery to life.