What did Explorers Find at the Top of Llullaillaco Volcano?
The highest mountain in the United States, and in all of North America, is Mount McKinley in Alaska, 20,320 feet high. But there was once a house in South America that stood at a higher altitude even than the peak of Mount McKinley! Llullaillaco is a 22,057-foot peak in the Andes Mountains, between Chile and Argentina. In 1961,
