The mummies were buried in dry, mineral-rich soil in the state of Guanajuato. Some still have hair, tanned skin and their original clothes.
"It is concerning that they are still on display without the safeguards for the public against biological risks," says an expert. They were dug up because their families could no longer afford burial fees, and they were put on display in the U.S. The mummies are believed to be between 600 and 800 years old.