Yellowstone National Park is packed with spectacular views, but one of it's most unique natural attraction is this gorgeous spring, with its rainbow-colored rims, thanks to a specialized bacteria that lives in it. It is the United States' largest hotspring and the third largest in the world. If you were thinking of taking a dip, think again - the average temperature is 158°F (70°C)...
6. Thor's Well, Oregon
Thor, the Norse god of thunder, is the namesake of this unique natural phenomenon that can be described as a natural water fountain. Thor's Well is located in an area called Cape Perpetua, and the powerful currents from the Pacific Ocean turn it into a spectacle, particularly an hour before and after the high tide.