Cave of the Bells lies in Sawmill Canyon on the eastern slopes of Arizona’s Santa Rita Mountains and is notable for an underground lake about 80 meters below its entrance. The lake has been measured at 76°F, or 24°C, and is thought to be warmed by sources below. Access is controlled by reservation, with permits and keys available through the Forest Supervisor’s Office. Nearby Onyx Cave is another point of interest in the same area.