Step 1 : Introduction to the question "Which national park can visitors see a human skull-shaped rock?"
...Joshua Tree National Park is a vast protected area in southern California. It's characterized by rugged rock formations and stark desert landscapes. Named for the region’s twisted, bristled Joshua trees, the park straddles the cactus-dotted Colorado Desert and the Mojave Desert, which is higher and cooler. Keys View looks out over the Coachella Valley. Hiking trails weave through the boulders of Hidden Valley.