The tradition of throwing things into the pool dates back to 1872, when the park first opened, according to Yellowstone National Park historian Alica Murphy. She claimed that tourists have always been known for throwing objects into the pool, hoping for either good luck or to prompt a geothermic event.

Once a brilliant blue, the famous pool's color has changed after decades of damage by the national park's visitors.

Tourists have ruined one of Yellowstone’s most gorgeous thermal pools — turning its once pristine blue waters into a mishmash of colors because of years of accumulated coins and trash, officials said.