 He directed teams that recovered four Inca human sacrifices on Ampato (20,708 ft) in southern Peru, including the Mummy Juanita (the "Ice Maiden").His expeditions in the Andes during 1996–1999 led to the discovery of fourteen more Inca human sacrifices on five mountains above 18,000 ft.In 1999 he directed the excavations of three of the world's best preserved mummies at over 22,000 feet (6,739 m) on Llullaillaco, the world’s highest archaeological site.