Fodor's Expert Review Morning Glory Pool
Shaped somewhat like a morning glory, this pool once was a deep blue, but the color is no longer as striking as before due to tourists dropping coins and other debris into the hole. To reach the pool, follow the boardwalk past Geyser Hill Loop and stately Castle Geyser, which has the biggest cone in Yellowstone. Morning Glory is the inspiration for popular children's author Jan Brett's story Hedgie Blasts Off, in which a hedgehog travels to another planet to unclog a geyser damaged by space tourists' debris.