9 Amazing Underground Attractions Around the World

Running 124 miles (200 kilometers) and 65 feet (20 meters) under the 14th, 15th, and 16th arrondissements in the City of Light, the Paris Catacombs are home to bones from more than 6 million bodies. Why were the catacombs built, you may wonder? The city's overflowing cemeteries caused a sanitation crisis in the 18th century that led the government to move the bones to an existing network of abandoned mines and passageways that ran under the city. The bones were transferred to underground quarries and neatly arranged, creating a haunting display, inadvertently creating spooky caves and tunnels that have become an urban underground adventure destination for tourists. Book a skip-the-line guided tour to learn more about its macabre history.

One of Poland's most visited tourist sites, The Wieliczka Salt Mine is a UNESCO World Heritage Site and was one of the oldest salt mines in operation (over 700 years) until it ceased production in 2007. Here, you'll see salt-carved chambers, caves and tunnels, and brine lakes on this fascinating trip 442 feet (135 meters) beneath the medieval town of Wieliczka. This subterranean landmark, just a half-day trip from Krakow, is best explored on a guided tour to learn the most about its history and explore the intricate details of the St. Kinga's Chapel, a religious sanctuary carved entirely from salt deposits that include salt chandeliers, sculptures, altars, and a bas-relief depicting the "Last Supper."

Rated as one of the best things to do in London, the Churchill War Rooms offers a chance to experience the bunker that sheltered then–Prime Minister Winston Churchill and his war cabinet during German bomb raids. This underground historical site, located below the streets in Westminster, was used as the headquarters to strategize the Allied route to victory during World War II. Don't miss the Map Room, which has remained in the same condition since 1945.

Insider tip: You can also see the rooms as part of a historical London walking tour.

Exploring underground cities sounds like something out of a sci-fi adventure book, but the 20-mile (32-kilometer) network of shops, restaurants, and other entertainment attractions underneath the streets of downtown Montreal is one of the largest underground pedestrian networks in the world. More than just a refuge in the city's freezing winter months, this subterranean attraction provides a home for artistic displays, event spaces for festivals and cultural events, as well as a link to the city's subway and bus system, all without stepping outside. Wander the sprawling space and check off underground sightseeing from your bucket list. Join a guided Montreal city tour to learn more about this below-the-surface attraction.

This natural sinkhole, with an open top to the sky, is part of Ik Kil Archeological Park and is also known as the "Sacred Blue Cenote," thanks to the vibrant color of its water and its history as a Mayan religious site. Climb down curving stone stairs to cool off in the subterranean freshwater pool, which is 200 feet (60 meters) in diameter, about 157 feet (48 meters) deep, and surrounded by lush hanging vines.

Insider tip: Various tours from the Riviera Maya or Cancun include visiting the cenote as part of a day trip to nearby Chichen Itza.

Discovered by two teenagers while running after a ball during a cricket match in 1907, the Crystal & Fantasy Cave is one of Bermuda's most stunning natural wonders and a popular underworld attraction. This unique underground cavern in Hamilton Parish is home to dripping stalactites and shimmering crystal-clear water.

Insider tip: Check out a Crystal Caves tour, some which also include exploring the capital city, Hamilton.

Dating back over 2,000 years, the Turda Salt Mine (a 4.5-hour drive from Bucharest) is the largest in the world. This offbeat underground destination, located 368 feet (120 meters) below the earth's surface, also functions as a subterranean amusement and wellness park with a Ferris wheel, an actual lake for boating, a bowling alley, and even a halotherapy (salt therapy) spa.

Insider tip: You can explore the Turda Salt Mine as part of a day-long tour that also includes a stop at Turda Gorge and lunch in the village of Rimetea.

Dating back to the 3rd century BC, The Golden Temple of Dambulla is the largest and best-preserved cave temple complex in Sri Lanka. Five caves were converted into temples and are now a UNESCO World Heritage Site. In addition to visiting this underground wonder, you'll see a 100-foot-tall (30-meter-tall) Buddha gilded in gold at its entrance, mural paintings on the cave walls, and more than 150 statues honoring Buddha, gods, goddesses, and royalty. You can visit the caves on a day tour from Kandy to Sigiriya.

Just a little over a 2.5-hour drive from Auckland, you can go underground to see the walls of the Waitomo Glowworm caves beautifully glow with blue-green light generated by the high population of glowworms. Waitomo, a Maori word that translates roughly to "water passing through a hole," is exactly what you'll experience on a tour of Waitomo Caves, thanks to a boat ride that gently glides along the river through the underground complex. Make sure to spend some time in the Cathedral space, where the acoustics are so good local choirs routinely perform there. Quite possibly one of the most unique and best underground attractions in the world, this destination is definitely a must-go if you find yourself in Auckland.