Morning Glory Pool, Yellowstone National Park
Long favored destination for park visitors, this glory pool was named in the 1880s for its remarkable likeness to its namesake flower. This blue pool soon became victim to vandalism; over the years people have thrown tons of coins, trash, rocks, and logs into the pool. Much of this debris became embedded in the sides and vent of the spring, which reduced the water circulation and thus the water temperature. Vandalism has decreased, but remains a problem. Natural changes may be cooling the water too. Cooler temperatures allow orange- and yellow-colored bacteria to thrive.
Upper Geyser Basin @ Old Faithful Area, Yellowstone National Park
David's thoughts about this picture selected in his top 25 of 2010:
It's no doubt in my mind that the photo made in his top 25 list. No describe for me to say about this Morning Glory Pool, located Old Faithful Area in Yellowstone National Park.