This one features Morning Glory Pool at Yellowstone. The hot spring pool is famous for it's intense blue color in the center. Over the years tourists dumped trash in it which reduced the temperature allowing the yellow and orange bacteria to spread further towards the center. The park has had to clean out the trash, unbelievable that anyone would throw waste into this wonder. When we were there this fall it was a nice vibrant blue at the center, and as seen here the yellow and orange color on the sides really popped.