USA/WY: Yellowstone NP – Mammoth Hot Springs
Mammoth Hit Springs are a unique spot in northern Yellowstone National Park – a series of travertine limestone terraces and pools with hot waters springs running down them. It took thousands of years for the terraces to grow, as the hot calcium-rich water deposited the material in neat pools, terraces, and staircases. The springs spout water at 80 degrees Celsius, and heat-loving orange algae thrive in this environment, coloring the terraces and walls in bright orange. The entire area is massive with multiple springs and takes several hours to fully explore.