Fort Rock State Park

Oregon usually brings to mind lush emerald wilderness, but one of its most prepossessing landmarks is located on the Oregon high desert plains. Fort Rock, so named because of the fortress-like walls, is a gigantic tuff ring, formed from the marriage of magma with the muddy floor of a prehistoric sea. It's not the most convenient place to travel to, and will require taking alternative routes, but it is a great day-trip for hikers and explorers.