Caves are some of the most beautiful, and least photographed, natural phenomenon in the world. Formed by water flowing over soft rock – or hot lava melting rock and forming holes – these cavernous structures take hundreds of thousands of years to form … and they’re definitely vacation-worthy destinations. Whether you’re looking for an adventure with friends or family, cave exploring is a fun and unique experience that requires little-to-no experience.

With many famous caves in the United States, you may not have to travel too far to experience the mystery and intrigue of caving. We’ve rounded up some notable destinations to explore the earth from a new level.

Mammoth Cave National Park

The first humans walked through Kentucky’s Mammoth Caves some 4,000 years ago – led by curiosity and wonder. It’s that same curiosity and wonder that leads hundreds of thousands of visitors through the caves today. All cave tours at this park are guided and offered at many different experience levels, from beginner to advanced. Check out the list of tours, and make your reservation before you get to the park. If you’re claustrophobic, or if heading into the dark unknown doesn’t excite you, there are plenty of other activities in the park, including hiking, fishing, and horseback riding.

Tip: Long pants and a light jacket are recommended for all cave tours, as the temperature in the caves ranges from below freezing to about 60 degrees depending on the time of year.

Carlsbad Caverns National Park

Out West in New Mexico, Carlsbad Caverns became a National Park in 1930, but had visitors traveling through thousands of years before that. Here, you can either embark on a ranger-guided tour or self-guided tour. We encourage you to do your research in picking the best experience for your comfort level. The self-guided tours include the Big Room trail, which is the largest single-cave chamber by volume in North America, or the Natural Entrance trail, which includes a steep descent of 750 feet. Ranger-guided tours range from easy to moderately difficult, and all equipment that may be needed is provided.

Tip: Turn your phone on airplane mode when you head into any cave tour, otherwise you phone will continue to search for a cell signal and drain your battery.

Polar Caves

Polar Caves Park in Rumney, N.H., was created during the Ice Age when a continental glacier descended over New Hampshire’s White Mountains. Not only can you explore the caves here, but visitors also can go on a scavenger hunt for minerals and hidden gems at the Klondike Mine, hike nature trails, learn about the local Native American tribes and visit the Maple Sugar House and Museum. If that doesn’t say fun-filled family vacation, we don’t know what else would!

If you’re looking for other great caves to explore, check out this list of incredible U.S. caves and caverns from the Travel Channel. Have you been on a caving adventure? Share your tips and top spots with us and other Fast Park guests on our Facebook page.