In the Biscuit Basin area you will find a foot bridge that crosses over to the Sapphire Pool. Before the 1959 earthquake , the Sapphire Pool was a geyser that erupted to heights of 10 to 12 feet.
Castle Geyser is a huge cone-type geyser (120 feet around) and looks like the ruins of an old castle tower. It erupts to heights from 60 to 100 feet.
