7 secret underground cities around the world you can actually visit

When one thinks of cities, towering skyscrapers and crowds rushing from one direction to the other come to mind. But did you know that in the bygone eras, people lived in underground cities? Forgotten tunnels, ancient civilizations and cities designed to shelter refugees during war, there are various underground cities in the world. These are the 7 secret underground cities across the globe that you can actually visit.

Located in Northern France, the secret underground city of Naours was built in a chalk quarry that dates back to the 15th century. It consists of caves dug by villagers to hide during wars and was first used as a residence during the Thirty Years War of the 17th century. The city also served as a residence to the German soldiers during World War II. Naours has 300 rooms, 28 galleries and once accommodated up to 3,000 people.

287 miles long and 1073 feet downward lies the Wieliczka Salt Mine in Poland. First excavated in the 1200s upon the orders of King Casimir III the Great, the ancient salt mine is known for the world's biggest cave chapel of St. Kinga, a replica of Da Vinci's The Last Supper and extravagant sculptures and chandeliers. However, what catches the eye about this UNESCO World Heritage Site is the fact that all these structures have been crafted from the alt crystal deposits within the walls.

During the rising Sino-Soviet conflict in 1969, Chinese Communist Party chairman, Mao Zedong advised the civilians to dig deep tunnels to store food and prepare for war. Almost 300,000 Chinese people then created the massive network of tunnels underneath the city of Beijing that is often called the 'Underground Great Wall of China' It can house 6 million people and has everything from schools to theatres, restaurants and farms.(Representative Image)

The secret underground city of Derinkuyu remained a secret from humans for quite a few years. It was discovered in 1963 when a local man found an adjacent dark tunnel to his wall during renovation. That tunnel was a part of this underground city that has a depth of 280 ft and 18 stories deep. It was operational until the early 20th century when the Cappadocian Greeks were chased out of the city. It has the capacity to house 20,000 people and has wineries, stables, chapels and schools.

Located in Scotland, the Edinburgh Vaults are a secret network of underground chambers and passages constructed under the 19 arches of the popular South Bridge. These chambers were selling points for traders and merchants whose souls are considered to be moving around them still. The Edinburgh Vaults were discovered in the 1980s and since then have become popular haunted tourist destinations.

RÉSO in Canada can be considered one of the most modern underground cities in the world. Stretching over 20 miles under the city of Québec, the underground city was originally created in the 1960s to provide relief from the brutal winters but was later rebranded in 2004. It is now a popular tourist spot with over 2000 stores, 200 restaurants, theatres, art galleries, a library and more.

The Cliff Palace at Mesa Verde, USA was built by the ancestral Puebloans who inhabited it during the 12th century. It is located under a cliff and may have been a protective residence. While the settlement has been weathered by natural processes it still is protected by the Mesa Verde National park.