Where's the volcano?

 After passing mile after mile of rugged lava flows en route to the Monument, you may expect to find a gigantic volcano with steep slopes and a summit crater -- like Mount St. Helens -- when you get there. But the volcanoes at Craters of the Moon do not fit that description. The eruptions there, called "fissure eruptions", occurred along cracks in the earth's crust. The eruptions were of very fluid basaltic lava from which gases could easily escape. Without high gas pressure, eruptions tend to be very mild and produce small cinder cones and extensive lava flows. There are more than 25 cinder cones at Craters of the Moon, each one a small volcano.