Point Reyes, CA
Distance from SF: 60 miles; 1.75 hours (plus a 3.5-mile, round-trip hike)
Start your journey at the McClure’s Beach trailhead and follow the path until you reach the beach. Then, take a left to walk south to Elephant Rock and the cave. To see how Elephant Rock got its name, walk past the cave area and take a look back.
NOTE: Both Point Reyes caves (Secret Cave and Elephant Cave) are blocked off by water except at the lowest tide levels. Consult tide tables closely before visiting. You can actually get trapped in Secret Cave, so be adventurous, but also don't be stupid and get yourself hurt. Also: water-safe clothing and water shoes are advised, as your cave explorations may look something like this.