Sequoia National Park in California, with more than 200 marble caverns, hides half of California’s caves, most of which are not open to the general public or require caving experience in order to explore them.
Fortunately, one of these treasures, and possibly one of the more exciting ones, can be visited from May to November (guided tours only!), and all you need is a jacket (there is a constant temperature of 48°F/9°C inside), comfortable shoes and a ticket in order to pass through the spider-web shaped gate that leads to it.
We are talking about Crystal Cave, discovered in 1918 and visited by thousands of people every year. Different tours are offered, ranging from a standard 50-minute visit (easy and suitable for everyone) to the more adventurous and aptly named “Adventure Tour”, for which you’ll need kneepads and elbow pads (provided) in order to crawl and climb through the narrow passageways.
Tours must be planned in advance and tickets must be bought at the Lodgepole or Foothills visitor centers, as they are not sold at the cave.