Meandering the streets of a new city is a great way to feel its pulse, but have you ever considered what's right below your feet? These thirteen underground, man-made attractions, scattered around the globe, boast spectacular histories as former dwellings, burial grounds, and even smugglers' tunnels. And you can bet they're more than a little creepy. You'll want to make sure you dress warmly for all of them (no matter when you visit), and be sure to arrive armed with a steely constitution. —Amanda Oppold
One of the pivotal settings in Dan Brown's book "Inferno," the Basilica Cistern in Istanbul is an awe-inspiring historical sight. Built in 532 AD, the cistern was used to store water for the Great Palace of Constantinople and other buildings. The cistern, located near the Hagia Sophia mosque, has a capacity of 100,000 tons of water, although today the bottom is only filled with several feet of water. Supported by 336 eerily lit marble columns, the cistern commands a majestic presence as you walk along the raised wooden platforms and see the fish swimming smoothly through the shadowy water. Make sure to check out the popular and mysterious Medusa head pedestals whose origin and orientation continue to baffle experts today.
RELATED: 6 spooky towns to visit this fall
In the late 18th century, Paris had a dire public health problem due to a large number of unburied corpses. Parisians sought the solution underground in quarries that had supplied the rock to build the city. Six million skeletons were exhumed and arranged in the catacombs, which are as deep as a five-story building, and include artistic arrangements of skulls and bones — don't miss the giant urns made of skeletal remains. Although much of the 200-mile network is out-of-bounds to the public, the 45-minute tour is a great peek. Make sure to arrive early, as the attraction is incredibly popular.
City Hall Subway Station
For a ghostly architectural gem in New York City, hop on the downtown 6 train and stay on past the end of the line at Brooklyn Bridge. As the train loops around, you'll pass by gorgeously decorated arches, skylights, intricate colored glass tilework and burnished brass light fixtures in the now-unused City Hall station. The station was opened in 1904 and was meant to be the crown jewel of the new subway, but due to low traffic numbers and an unsafe gap at the platform, the station was closed in 1945. The mystique and spooky, abandoned beauty of this hidden jewel is well worth the train ride.
The Cu Chi Tunnels
During the Vietnam War, the communist guerilla Viet Cong were vastly outnumbered and equipped with inferior technology compared to the American and South Vietnamese troops. To combat this, the Viet Cong expanded tunnels created during an earlier war against the French, and used these underground routes to house troops, transport supplies, and lay booby traps. The residents of Cu Chi slept, ate, wed, and even gave birth in these underground abodes to avoid detection. While getting to the tunnels is a bit of a trek (expect a 2.5-hour bus ride from Ho Chi Minh city), the tour and tunnels are an amazing sight. Make a day out of it by combining the tunnel tour with a trip to the nearby elaborate Cao Dai Temple.
For one of the eeriest sights in the world, visit Rome's Capuchin Crypt. Beneath the church of Santa Maria, you'll find the skeletal remains of 3,700 Capuchin friars. In 1631, when the monks moved to the church, they brought cartloads of deceased friars to be arranged in the burial crypt. Over the course of years, a cyclical process developed where long-dead friars were exhumed to make room for recently deceased friars' burials, the exhumed bones were then placed into the crypts' elaborate designs. What makes this crypt more chilling than the Paris Catacombs is the true artistry and intricate displays in the six crypts. Enter the crypt and gaze upon artwork all framed by various human bones, skull chandeliers, and intricate bone designs. Visitors must wear modest clothing and be prepared for a macabre scene.
Wieliczka Salt Mine
One of the world's oldest operational salt mines, Wieliczka near Krakow, Poland, is more than 700 years old. The mine is a UNESCO World Heritage site and features dozens of beautiful sculptures, 20 chambers, three chapels and an entire cathedral carved into the rock salt. Visitors should be ready for a workout as you will descend 800 steps into the mine (don’t worry, there's an elevator to take you up). Enjoy listening to Chopin and watching a light show play on a saline lake, or admire the incredible Chapel of St. Kinga. Adventurous guests can choose the Miner's Route tour and act the part of a real miner. The mine is also renowned for its health benefits and features a health resort that offers subterranotherapy — a treatment created at the mine that uses the underground environment's medicinal properties to treat respiratory illnesses and balance the body.
Hidden beneath Edinburgh's South Bridge are over 120 rooms that were used as secret living places for the Scottish city's poor. The vaults were originally meant as a storage space for local businesses, however they flooded, conditions deteriorated and Edinburgh's slum dwellers became the new inhabitants. The passages and vaults also gained a reputation as a renowned red light district until they were closed in the late 19th century. Since their rediscovery in 1988, visitors have reported ghostly sightings. Take a tour of these haunted underground abodes and you may feel the presence of a former inhabitant.
For the rest of the best creepy underground attractions, including the dual histories of Saskatchewan's tunnels, visit Fodor's.