The Great Boiling Spring is a natural geothermal pool on the edge of Gerlach, fed by the volcanic heat that warms the entire region. The water bubbles up at near-boiling temperature, releasing steam into the desert air. The spring was well known to emigrants on the Applegate-Lassen cutoff who used it as a campsite landmark and to boil water before crossing the playa. Today it sits on private property adjacent to the highway; you can see it from the road and its overflow feeds the soaking pools further downstream.