On March 16, 1999, National Geographic Society Explorer-in-Residence Johan Reinhard and his team could finally rest for a spell. They had spent three days in heavy snowfall and ferocious winds atop the more than 20,000-foot-high summit of South America’s Mount Llullaillaco, searching for this very site. But they could not have been prepared for what they would eventually uncover: 5 feet beneath the rocks lay what Reinhard has since called “the best-preserved Inca mummies ever found.”