Darwin Falls (lower) mainly divided into the upper and lower with a small grotto in between. At a combined 80 feet (24 m), it is the highest waterfall and fed by one of the four perennial streams in Death Valley National Park. The canyon is walled by plutonic rock (a body of intrusive igneous rock that crystallized from magma slowly cooling below the surface of the Earth). Death Valley National Monument Est. February 11, 1933. Est. as Death Valley National Park in 1994; 5,270 square miles (13,649 km2). Inyo County, CA.