Yellowstone National Park's network of hot springs, pools, and geysers are one of its main attractions, and are the reason the park was first created, but despite the best efforts of Park Rangers, they are often subject to littering and defacement. The beautiful Morning Glory Pool in the Upper Geyser Basin is a particular hotspot for vandalism ever since the park first opened in the late 1800s.
Back then, the water was a deep, rich blue color, which led to the pool being named after the morning glory flower. However, as the National Park Service explains, people have thrown thousands of pounds of coins, trash and rocks into the steaming water over the years, much of which has become embedded in the pool's sides. All this junk has constricted the water flow and lowered the overall temperature of the pool, which has gradually shifted to green and orange as the type of bacteria have changed.
