EXTRAORDINARY CAVES YOU CAN SNORKEL, DIVE, AND HIKE IN AROUND THE WORLD

Conservationists will appreciate a trip to the Punta Sal National Park (a one hour boat ride from Tela, Honduras), as it’s home to the highest density of critically endangered elkhorn coral in the Caribbean. Also inside the Punta Sal are three 118-foot-deep volcanic rock formations called farallones that house underwater caves. Visitors can follow the ocean currents and swim through them, while divers may even spot hammerhead sharks.

Rumored to have been used as a shelter by Native Americans and early settlers, the Smallin Civil War Cave in Missouri has the largest cave opening in the state. A guide takes guests off-trail through 54-degree water, over rimstone dams and through areas of the cave that are beautiful but difficult to access. Spot the eerie mushroom formation made of calcium carbonate, and watch for rare bristly cave crayfish and blind salamanders. The Civil War Lantern Tour includes a dinner of beans and cornbread while guests sit around a campfire to hear history tales, followed by a tour of the cave.

For the truly adventurous, the Aventuras Mayas tour company leads guests on a snorkeling excursion through a 100,000-year-old cave has an underground river with crystal clear waters. Peer below the surface and see stalagmites rising up from the cave floor, while icicle-like stalactites cling to the cave ceiling overhead. Nearby, a massive network of underwater caves has recently been discovered — and the rooms are filled with ancient Mayan artifacts.

Inside the Longyear Glacier, travelers can embark on a frosty trek through corridors and channels carved by rushing water through the ice. Using a headlamp to illuminate the passages, you’ll walk (and occasionally crawl) through the wintry realm.

Park City Yoga Adventures takes visitors deep inside the 10,000-year-old Homestead Crater in Park City, Utah. Julia Geisler, the founder, will demonstrate yoga poses from the dock with guests practice on stand-up paddleboards that float on the 95-degree hot spring water. Park City Yoga Adventures also offers a one-and-a-half-hour hike or snowshoe through Utah’s forests before warming up inside the crater.

China’s Linwu Caves are located on Xishan Island, in the middle of Suzhou’s Taihu Lake. The cave consists of four interconnected limestone caverns with springs, a stone moat, bridges, and other recognizable features. Because the caves are a comfortable 68 degrees year round, it is a popular place to cool off in the summer. Because Xishan Island has historically been considered a sacred spot by practitioners of Taoism, many believe these were the training grounds of the famed fighting monks. (Legend has it, they were so well-versed in the martial arts they could kill with a flick of the wrist.) In fact, monks do still live in the area — and Yu Jian and Tang Dynasty Taoist relics have been found inside the caves.

Chile’s Cuevas de Mármol (or Marble Caves) are located in a remote region of Northern Patagonia, and were formed some 6,000 years ago. The caves border Lago General Carrera, a remote glacial, and can only be reached by boat. Inside, intrepid travelers will be rewarded by the cave’s hypnotizing pattern of blue, white, and yellow swirls — and crystal clear waters that change in hue throughout the year.

At the Lava River Cave in the Coconino National Forest in Flagstaff, Arizona, visitors can self-guide their way through the cave by walking, scrambling, and crawling for more than a mile underground. The Lava River Cave was named after the molten rock that erupted from a volcanic vent in nearby Hart Prairie approximately 700,000 years ago. Because the cave is always cool (about 42 degrees Fahrenheit even in summer) visitors should watch out for slick spots of ice. At least a few sources of light, including headlamps, are recommended, as it’s pitch black inside.

Arrange a trip to Viñales, in western Cuba, with Cuba Travel Network. Here, just 45 minutes from Havana, travelers can board motor boats to reach the Cueva del Indio caves, which are filled with butterfly bats, albino fish, and the fossils of Pleistocene mammals. The tour culminates with a boat ride through the underground labyrinth of canals. (Expect your guide to supplement the tour with spooky tales.)

Coasteering describes the daring activity of scaling, scrambling, and climbing along the coast. At the Pembrokeshire shoreline in Wales, you can scale cliffs and rocks, and there is section where you also swim into sea caves. These sea caves were formed when weaknesses in the underlying rock were eroded by the ceaseless waves — and now they are an important habitat for gray seals giving birth to their pups and sea birds that use the ledges of rock to nest. Geared up in a wetsuit, helmet, and buoyancy aid, part of the tour involves jumping into ‘The Washing Machine’ where the water swirls around like, well, a washing machine.

Australia’s sparkling limestone Cutta Cutta Caves are located 50 feet underground, and date back one million years. These geological formations are home to a variety of wildlife ranging from the brown tree snake to five different species of bats (including the rare ghost and horseshoe bats). After exploring the caves, travelers should save time for the Cutta Cutta Caves National Park’s self-guided tropical woodland walk offers information about the local flora and fauna.

Semuc Champey is a flooded caving system where you can carry a lit candle and walk through the dark Kan’Ba Caves. Inside, visitors will cross a series of limestone bridges and enter caves that snake beneath central Guatemala. There are also a number of tiered, turquoise pools fed by the waters of the Cabahón River. After walking through the caves, take a swim swim behind the Semuc Champey waterfalls.

Visitors to Portugal’s southern region, the Algarve, can embark on a boat tour of the Mediterranean nation’s coastal caves. There are radical spins and turns during the two-hour-long Dreamwave boat cruise, which travels between Albufeira Marina and Carvoeiro. These caves are large enough to accommodate the boat, and your guide will share interesting facts about the location and history. On occasion, you may be joined by equally curious dolphins.