Yellowstone's Morning Glory Pool Altered by Decades of Tourist Debris

The once-blue geothermal pool has changed color due to coins, trash, and rocks thrown by visitors since the park's opening.

The Morning Glory Pool in Yellowstone National Park has transformed from blue to yellow-green due to debris thrown by tourists.
Coins, trash, and even car parts have settled in the pool, blocking the hot water flow and lowering the temperature.
Lower temperatures have allowed different bacteria to grow, resulting in the pool's multicolored appearance.
The tradition of throwing objects into the pool dates back to 1872, with tourists believing it could bring good luck or trigger eruptions.
Efforts to clean the pool have been ongoing, but the original blue color has not returned, and future changes remain uncertain.