Far up in the north of California, at the southern edge of the Cascade Mountains, lies one of the state’s biggest—and steamiest—hidden treasures. This is Lassen Volcanic National Park, one hundred and sixty-five square miles of crystal clear lakes, striking mountain views, and bubbling geothermal activity. Lassen is special for many reasons, but particularly rare is the fact that here, you can visit all four types of volcanos: plug dome, shield, cinder cone, and composite. It’s one of the few places in the world—and the only park in the United…
