This national monument's crowning feature is the geological formation of the same name made of columnar basalt. The unusual and alien striations were caused by the rapid cooling of lava around 100,000 years ago. At the top visitors can see the eerily symmetrical hexagonal shapes of the column cross-sections. To get there you'll take Hwy 395 to Route 203. Follow 203 for about 15 miles (past Minaret Falls Campground) and make a right on Devils Postpile Rd. This road will take you to the parking lot. Keep in mind that these roads will be closed during winter. See the nps.gov website for updates on openings/closures.