Why obsess with taking your next vacation somewhere above ground, when you can go and explore somewhere underground? There are many interesting places and attractions that are truly epic across America that are worth going to visit at least once. And since the winter months are settling in, this may be a great time to explore them. Check them out!

Take a stroll to Greenbrier Bunker, West Virginia for a tour at the Greenbrier resort. Behind the 18-ton blast proof doors is a bunker which was part of a top-secret project in the late 60s. It could house up to a 1000 people, including the US Senate.

Onondaga Cave, Missouri: There is a beautiful subterranean world under the belly of Cave State Park. It isn’t as commercialized, so don’t expect a fancy tour, but it is still enchanting.

Dinosaur Caves, California: Go on a 3 hour excursion through the San Luis Obispo County stretch of the California coast home. It’s possible you’ll spot seals, otters, and dolphins.

Old Sacramento Underground, California: During the 1800’s, Sacramento faced a powerful storm. Afterwards, locals spent years raising the streets and homes nine feet. Now, you can see some of what old Sacramento was like under the streets and alleys.

Inner Space Caverns, Texas: In 1963, the Inner Space Cavern was found in Texas. Go there now to check out the chambers, sharp stalagmites and pools.

Indiana Caverns, Indiana: Go on a 4-hour deep dark tour in Indiana. There are lower caves in Indiana where you’ll see boulders and watery passages.

READ MORE: America’s Underground Attractions You Didn’t Know Existed