It is not a rumour. There are still in existence underground cities on planet earth. Many of these cities dates back to centuries and were used for various activities.
Legit.ng presents stories behind some of these mystery underground cities and where they are situated.
1. Derinkuyu, Cappadocia, Turkey
Cappadocia city located in Turkey is said to have about 36 underground cities, Momondo reports.
Discovered in 1963 and opened to members of the public in 1965, the Derinkuyu underground city is the deepest.
It was said to have accommodated over 20,000 persons many years ago. It has different institutions one can find in a regular city including stables, wineries, storage rooms and so forth.
2. Shanghai Tunnels, Portland, United States
Located in Portland, in the United States is another underground city known as Shanghai Tunnels.
The underground city many years ago is rumoured to be home to Shanghai - an act of kidnapping people for them to serve as sailors.
Now, it is a good tourist destination. It has hotels, bars and so forth.
3. Naours, France
The underground city of Naours, located in the northern part of France has about 300 man-made rooms, History.com reports.
Hidden 100 feet below, it began life in the third century A.D as part of a Roman quarry but took the form of a village as locals used it as a hiding place during periods of war and invasions that happened in the Middle Ages.
Bakeries, stables, wells are some of the things that can be found in this mystery city.
4. Wieliczka Salt Mine, Poland
The Wieliczka Salt Mine located in Poland is another interesting underground city. The site which dates to the 1200s is also referred to as the Underground Salt Cathedral. It was previously a salt-producing location until 2007.
Workers at that time used the salt crystals found on the site for chandeliers, bar reliefs and statues.
5. Beijing Underground city, China
Located in China, the Beijing Underground city was constructed by the Chinese government in the 1960s in reaction to impending war at that time, according to History.com.
It consisted of fallout-proofed tunnels and rooms, skating rinks and even a 1000-seat movie theatre. It was eventually opened for tourists in the early 2000s.
Meanwhile, Legit.ng previously reported that residents were awestruck as a 139-year-old building was moved to make way for another building.
In a clip that was shared on Twitter by @jrstonelive, residents could be seen watching the moment the old house was moved from 807 Franklin St to 635 Fulton St. San Francisco.
"Nothing to see here, just a historic San Francisco Victorian home coming down the street! Today it’s being moved 6 blocks for more than $400,000. It’s old location near Turk and Franklin will soon be home to more than 60 apartments."