text: Lassen Peak, a 10,457-foot (3,187-meter) volcano, in the Cascade Range in California, is lit by the first light of day in this aerial view over Lassen Volcanic National Park. Lassen Peak, also known as Mount Lassen, is an active volcano that last erupted in 1917. The area, however, is still volcanically active with hot springs, geysers and boiling mud pots. Lassen Peak itself stands near Mount Tehama, which was a stratovolcano that was once at least 1,000 feet taller than Lassen Peak is now. Mount Tehama is now known as Brokeoff Mountain, and is visible to the left of Lassen Peak in this image.