Morning Glory Pool--Most Beautiful Pool in Yellowstone National Park

Morning Glory Pool is the most beautiful springl in Yellowstone National Park. But, maybe some more years later, we can't see such a beautiful pool any more. Phillip Colla introduces on his website:

Morning Glory Pool, one of the most popular and beautiful pools in Yellowstone National Park, earned its name in the 1880's due to its deep blue coloration and likeness to the Morning Glory flower. Over the years visitors tossed coins, trash, sticks and rocks into the pool, causing its vent to clog and the flow of water to decrease. This prompted the temperature in the pool to lessen, causing the pool's deep blue color to fade and allowing the red and yellow algae that formerly only survived at the fringe of the pool to grow toward the center.