Hidden passageways, ancient tunnels, and urban legends – the underground teems with magical stories of a life that once was, and activities few people ever heard about.

Cappadocia city, located in central Turkey, is home to no less than 36 underground cities, and at a depth of approx. 85 m, Derinkuyu is the deepest. Discovered in 1963, the subterranean network of tunnels and rooms include all the institutions and rooms you would find in a regular city: living quarters, stables, churches, storage rooms, refectories, and wineries – and the underground is said to have possibly held more than 20,000 people.

Opened to the public in 1965, only 10% of the underground city is accessible for visitors. Unique to Derinkuyu is the cruciform church located between the third and fourth level and the barrel-vaulted ceiling.

Portland has its own underground city known as the Shanghai Tunnels, or the less common name: the Portland Underground. This intricate network reportedly once consisted of tunnel passageways linking Portland’s Old Town, also known as Chinatown, to the central Downtown area. Unfortunately many of these subterranean spaces have been filled in during various public works projects, but a few of them are still there and open to explore.

Back in the day, the basements of many a downtown bar and hotel were linked to the Willamette River waterfront by way of these tunnels, allowing supplies to be moved from docked ships directly to basements for storage, thus avoiding rain and heavy traffic. Though still a controversial topic, rumor has it the tunnels have also been used for the practice of “shanghaiing”: kidnapping people for them to serve as sailors. Beneath the streets of Scotland’s capital lies a dark and damp world, dating back to the 18th century. The Edinburgh Vaults, also known as The South Bridge Vaults, are a series of chambers formed within the 19 arches of South Bridge. Opened in 1788, a period of great expansion and growth, the vaults date back to a time when Edinburgh was a superstitious place. Today, they still exude a feel of gore and ghastliness. Originally built to house taverns, cobblers, cutlers, smelters and other tradesmen, and to store illicit materials, rumors have it that serial killers Burke and Hare also stored various bodies down here, which they sold for medical experiments. Later, when the businesses moved out, the vaults became home to the city’s poorest souls, a skid row complete with pubs and brothels scattered around the wet chambers. A place so grim it would make any of today’s red light districts seem nice and snug. Beijing’s underground city, Dixia Cheng, was built in the 1970s to serve as a shelter during invasions, bombings and nuclear attacks. The lengthy network of tunnels, often referred to as the Underground Great Wall, included almost 100 hidden entrances and, reportedly, were built with complete services such as schools, hospitals, and sleeping halls in case citizens needed to seek refuge for a longer period of time. Fortunately there never was an occasion for this massive underground shelter to fulfil its intended purpose, and in 2000 the place was opened to the public. A tour only includes a small circular stretch of the complex, but is still attracting travelers from around the world. Dixia Cheng has been under renovations since 2008 and therefore closed for visitors, but make sure you put it on your bucket list to check out when it reopens at an indefinite date in the future.

Located in the town of Wieliczka just over 9 miles outside of Krakow, the Wieliczka Salt Mine was built back in the 13th century and has produced table salt continuously until 2007.

One of the biggest tourist draws of Poland, this underground salt city has evolved from a series of dark caves to a complex labyrinth now comprising over 185 impressive miles of galleries, about 3000 chambers and nine floors, with the first three open to the public.

Once you descend the 378 steps wooden staircase, you’ll be greeted with a vast variety of guided tour options: If you’re interested in the history of the salt mine, take the Miners’ Tour and get insights into the difficult profession of a salt miner. Alternatively, if you want to learn more about the religious aspects, join the Pilgrims’ Tour that includes a visit to the salt statue of John Paul II and a Holy Mass upon the end of the tour. RÉSO, stemming from the French word réseau, meaning network, is one of Montreal’s cornerstones. This giant maze runs under Montreal’s streets in and around the Downtown area and houses a wide-range of shops, restaurants, hotels, galleries, seven metro stops, cinemas, a library and even apartment buildings. The first interconnected sections were built in 1962 with the objective of easing traffic and providing a sheltered way of transportation, especially handy during the harsh winter season. Since the Montreal Metro started operating in 1966, more connections have been added and today RÉSO consists of 20 miles of tunnels with more than 120 exterior access points. Apart from going shopping, come around to check out the permanent artworks on display, public squares and cultural centers. If you want to discover all the hidden spots, book a guided tour and start walking.

Chinese archaeologists have unearthed six underground cities – one on top of another – from several dynasties spanning more than 2,000 years in central China.
The ancient cities, believed to have been built during the Warring States (475-221 BC) to the Qing dynasty (1644-1911) periods, were excavated at the Xinzheng Gate site in Kaifeng, Henan province, on Saturday, the People’s Daily reported.

Underground Atlanta is a well-known shopping district now, but disappeared from the maps for many years. It was street-level back in the 1800s, but during the 1920s, concrete viaducts were built to accommodate the growing traffic flow of the busy city. The construction of the viaducts raised the streets a level and everything underneath was abandoned”¦ until the 1960s, when it was rediscovered. It’s a fun shopping and entertainment district today, but if you keep your eyes peeled, you can still see remnants of the past: hand carved wooden panels, decorative brick, granite arches and marble accents. It looks like Chicago could have an underground city of its own – or at least a mini one. In the late 1850s, residents of the Windy City were having issues with drainage and flooding because the city sat nearly even with Lake Michigan. The solution? To raise parts of the city up another four or five feet. And the real kicker was this: although the City of Chicago was paying for the street regrades, individual property and business owners were responsible for doing something about their own buildings. If you couldn’t afford it, tough. i bet if you know where to look, there’s plenty of interesting underground structures hidden just below the street.

After the Great Seattle Fire of June 6, 1889,[1][2] new construction was required to be of masonry, and the town’s streets were regraded one to two stories higher. Pioneer Square had originally been built mostly on filled-in tidelands and often flooded. The new street level also kept sewers draining into Elliott Bay from backing up at high tide.

For the regrade, the streets were lined with concrete walls that formed narrow alleyways between the walls and the buildings on both sides of the street, with a wide “alley” where the street was. The naturally steep hillsides were used and, through a series of sluices, material was washed into the wide “alleys”, by raising the streets to the desired new level, generally 12 feet (3.7 m) higher than before, in some places nearly 30 feet (9.1 m).

At first, pedestrians climbed ladders to go between street level and the sidewalks in front of the building entrances. Brick archways were constructed next to the road surface, above the submerged sidewalks. Vault lights (a form of walk-on skylight with small panes of clear glass which later became amethyst-colored) were installed over the gap from the raised street and the building, creating the area now called the Seattle Underground.

The concrete floor of the former meat market was originally at the level of the wooden platform on the left but sank over time because of decomposing sawdust fill.
When they reconstructed their buildings, merchants and landlords knew that the ground floor would eventually be underground and the next floor up would be the new ground floor, so there is very little decoration on the doors and windows of the original ground floor, but extensive decoration on the new ground floor.

Once the new sidewalks were complete, building owners moved their businesses to the new ground floor, although merchants carried on business in the lowest floors of buildings that survived the fire, and pedestrians continued to use the underground sidewalks lit by the vault lights (still seen on some streets) embedded in the grade-level sidewalk above.

In 1907, the city condemned the Underground for fear of bubonic plague, two years before the 1909 World Fair in Seattle (Alaska-Yukon-Pacific Exposition). The basements were left to deteriorate or were used as storage. Some became illegal flophouses for the homeless, gambling halls, speakeasies, and opium dens.[citation needed]