Frozen on a 22,000-foot volcano for 500 years, Inca child mummies may have been sacrificed to secure an empire

• Deep in the Andes, atop the frozen summit of Llullaillaco volcano on the border of Argentina and Chile, archaeologists once found the remarkably preserved remains of three Inca children sacrificed centuries ago.
• Now a new scientific analysis has pinned down almost exactly when this ritual took place, and why it may have happened.