If it’s your dream (or your wife’s) to belly-crawl through dark narrow cave passages, you’re in luck. The National Park Service has numerous Wild Caving guided tours where you can dive into an extreme underground adventure and explore places most people will never see. NPS sites with Wild Cave tours: South Dakota: Wind Cave National Park and Jewel Cave National Monument Kentucky: Mammoth Cave National Park Oregon: Oregon Caves National Monument Nevada: Lehman Cave at Great Basin National Park Ut