|Bear Gulch Cave at Pinnacles National Park|
The park preserves the spire-like remains of a rhyolitic stratovolcano that erupted around 23 million years ago. Long after the monument was established, geologists discovered an additional reason the region deserved park status: half of the volcano is in Southern California, 195 miles away! It turns out the volcano erupted on the San Andreas fault, and has been moving northward at the stunning (!) rate of about 2 inches per year.
|A sense of scale? The blue thing near the middle of the photo is a person!|