The world has many underground cities, including ancient cities, modern cities, and secret cities:

• Ancient cities: Beijing Underground City, Orvieto, Petra, Wieliczka Salt Mine, and Lalibela 
• Modern cities: Helsinki underground city, Dixia Cheng, and Napoli Sotterranea 
• Secret cities: Derinkuyu, Cappadocia, Turkey; Shanghai Tunnels, Portland, United States; and Edinburgh Vaults, Edinburgh, United Kingdom

Other underground cities include:

• Montreal’s Underground City, the world’s largest underground network 
• Canada Tunnels of Moose Jaw, Saskatchewan, a network of passages that some say were carved out by Chinese settlers 
• Midyat, Turkey, which has been home to many civilizations over the last 3,000 years

What is the world largest underground city

Derinkuyu, also known as Elengubu, is the world’s largest excavated underground city. It’s located in Cappadocia, Turkey, and is estimated to be at least 18 stories deep, with some areas extending as far as 85 meters underground. The city was in near-constant use for thousands of years, and was large enough to have sheltered as many as 20,000 people, their livestock, and food stores. It was finally abandoned in the 1920s by the Cappadocian Greeks

In 1963, a man discovered the city by knocking down a wall in his basement. The city has since become a UNESCO World Heritage site and attracts tourists, archaeologists, geologists, and ethnologists

Why are underground cities made

Underground cities have been built for many reasons, including:

• Environmental adaptation Underground cities can be practical in regions with extreme climates or harsh natural conditions. They can also provide a comfortable year-round environment in cities with very hot or cold climates. 
• Protection Underground cities can provide protection against external threats, such as nuclear fallout. For example, China and Russia built large underground cities during the Cold War in anticipation of nuclear fallout. 
• Resource management Ancient underground cities were often built near or within resource-rich areas. 
• Religious and ritualistic practices Underground cities have held religious and ceremonial significance for many ancient cultures. 
• Energy efficiency Underground construction is more energy efficient than above-ground construction. 
• Land space As the global population grows, available land space in urban areas is at a premium. Underground construction can free up land above ground. WikipediaUnderground city – WikipediaUnderground cities are especially functional in cities with very cold or hot climates, because they permit activities to be comfortably accessible year round without regard to the weather. Underground cities are similar in nature to skyway systems and may include some buildings linked by skyways or above-ground corridors rather than underground. Some cities also have tunnels that have been abandoned. 

Some advantages of underground living include: resistance to severe weather, quiet living space, unobtrusive presence in the surrounding landscape, and nearly constant interior temperature

Underground cities are especially functional in cities with very cold or hot climates, because they permit activities to be comfortably accessible year round without regard to the weather

Are there any modern underground cities

Yes, there are many modern underground cities, including:

• RÉSO, Montreal Underground City, Canada A 20-mile network of tunnels and buildings that covers over 41 city blocks and provides access to many attractions and amenities 
• Shinjuku, Japan A network of tunnels, passageways, and shopping malls built in the 1960s to reduce traffic congestion 
• Coober Pedy, South Australia Residents have built underground homes, churches, and hotels to escape the extreme heat 
• Singapore The Mass Rapid Transit has extensive underground networks around most major stations, including the Raffles Place MRT station, which connects to 19 buildings in the Raffles Place area 
• Cappadocia, Turkey This city is believed to contain nearly 150–200 underground cities, including Derinkuyu, which is 278 feet deep and a UNESCO World Heritage site 

Other modern underground cities include:

• Tenjin Underground City in Chūō-ku, Fukuoka, Japan 
• Shanghai Tunnels, Portland, United States 
• Edinburgh Vaults, Edinburgh, United Kingdom 
• Dixia Cheng, Beijing, China 
• Wieliczka, Poland

Montreal, Quebec, Underground City, or la ville souterraine in French, is the largest habitable underground network in the world

Canada is building RESO, the world’s largest underground city, in Montreal. It’s a 33 km (20 mile) pedestrian network that covers 12 square kilometers of downtown Montreal

Developers in Saudi Arabiaannounced plans Wednesday for the project, Aquellum. It is being billed as an underground city and tourist destination that “will offer guests a taste of futuristic living through its array of pioneering experiences

Yes, it’s possible to build an underground city, but it requires careful planning. Underground cities can be active modern creations or historic sites. Some examples of underground cities include: 

• Maastricht, Netherlands A centuries-old tunnel system that was used by Jews to hide from the Nazis during World War II 
• Derinkuyu Underground City, Cappadocia, Turkey Estimated to be at least 18 stories deep, with some areas extending 85 meters underground 
• Beijing Underground City, China A network of tunnels and chambers that spans over 33 square miles at a depth of 8–18 meters 
• Aquellum, Saudi Arabia An underground city and tourist destination that will be 330 feet tall and located within a 1,500-foot-tall mountain range 

Other examples of underground cities include:

• Coober Pedy, South Australia, where residents have built homes, churches, and hotels underground to escape the heat 
• Vast underground cities built by China and Russia during the Cold War to protect against nuclear fallout 
• Željava Air Base in former Yugoslavia, designed to withstand a nuclear bomb 

Underground cities require careful design to consider issues like water, sound, vegetation, and light. They also need precise planning, as unsustainable practices can have more disastrous consequences in a confined underground environment

Some say that humans aren’t biologically designed for life underground because we need a solid surface to walk on and air to breathe. Others say that living underground is inconvenient because it’s an extension of living in a cave, where you’re vulnerable when you need to get out for food and you need regular sunlight for vitamin D. 

Building underground is also more difficult than building above ground because underground buildings must support their own weight and push back dirt. Tunneling is also very expensive, costing millions of dollars per kilometer. Holes can also collapse if not dug carefully, and the slope into a trench can’t be more than 45 degrees unless shoring is involved. 

Some say that it’s unrealistic to have an identical underground city because of the technological and logistical challenges of maintaining interactions and commuting between the above and underground environments.

Mostly it’s because we were designed (or evolved) to thrive in the topside environment. We gain physical and mental health from the sun, air and flora and fauna we share the aboveground world with

Can a underground city survive nucleur war

According to scienceabc.com, modern nuclear weapons can destroy bunkers up to 1,000 feet deep, but the exact impact depends on many variables, including the bunker’s depth, material thickness, and the altitude of the explosion

According to Quora, while it might be possible to shelter from a nuclear blast in a deep tube tunnel or station on the London Underground, the systems that people rely on, like food and water distribution, would be broken after the blast. The radiation in the air would also likely make people very sick. 

According to ready.gov, the best places to be during a nuclear explosion are underground and in the middle of large buildings. They recommend identifying shelters to seek during a detonation while commuting, and looking for basements or the center of large multi-story buildings. Outdoor areas, vehicles, and mobile homes are not adequate shelters. 

Safeguarding Bunkers Against Nuclear ExplosionsThe farther a bunker is from the explosion’s epicenter, the safer it is from physical, thermal and radiation shocks. As the density of the earth’s surface increases with depth, so does its ability to decelerate penetrating weapons

Where is the safest place against nuclear war?

Scientists have recently revealed that Australia and New Zealand are best placed to survive a nuclear apocalypse and help reboot collapsed human civilisation. The study, published in the journal Risk Analysis. These countries include not just Australia and New Zealand, but also Iceland, the Solomon Islands and Vanuatu

Are there any underground cities on mars

There is no evidence of underground cities on Mars, but some scientists and architects have proposed plans for them. Underground habitats are a focus of off-planet colonization efforts because they offer protection from radiation, micrometeorites, and other hazards. For example, an architecture firm has proposed a sustainable city called Nüwa that could house up to 250,000 people in mostly underground cave systems

However, some say that it’s unlikely that Mars has had enough time for intelligent life to evolve in a stable environment, making the possibility of an underground civilization implausible. 

Some say that Mars may have underground lakes, with the largest one measuring up to 12 miles across. Mars also has underground caves, including the Hellas Basin Caves, which have a network of tunnels and chambers that rival Earth’s most intricate natural cave systems

As of April 2024, there is no evidence of life on Mars, past or present. However, some scientists say that Mars may have hosted underground alien life in the past and may still do so. A 2022 study suggests that organisms called “methanogens” may have lived in underground lairs on Mars billions of years ago, and may still exist. Other studies suggest that some hardy microbes may have survived underground in a frozen state

Some say that Mars’ surface environment may have been habitable for microorganisms during the ancient Noachian time period, when it had liquid water. However, Mars is believed to have lost its water when it lost its magnetic field around 4 billion years ago, and without an atmosphere, the water evaporated and was lost to space. This radiation also made life at the surface of Mars unfeasible

Currently, the surface of Mars is bathed with ionizing radiation, and Martian soil is rich in perchlorates toxic to microorganisms. Therefore, the consensus is that if life exists—or existed—on Mars, it could be found or is best preserved in the subsurface, away from present-day harsh surface processes

Are underground cities possible on moon

Yes, it’s likely that underground cities could be built on the moon if humans establish permanent settlements there. The moon’s surface is dangerous to human life due to solar radiation, so underground settlements would likely be mostly built underground

The moon has many caves, pits, and old lava tubes beneath its cratered surface. Research has shown that lunar caves are more stable than the moon’s surface, making them possible sites for future human colonization. 

Lunar lava tubes are formed when basaltic lava flows erupt and the lava channels beneath the surface of the flow as it cools and hardens. Once the lava flow decreases, the tube may drain and form a hollow void. A Purdue team found that lunar lava tubes with a strong arched shape, similar to those on Earth, could be stable on the moon at sizes up to 5,000 meters wide. This wouldn’t be possible on Earth because of its higher gravity and the need for lunar rock to withstand more weathering and erosion. Some lunar lava tubes could be more than 800 meters in diameter, which is large enough to house a human colony. 

China plans to build an underground moon base in one of the moon’s lava tubes, which would include residential and research facilities, and an energy and communication center at the entrance. 

Yes, a moon base would likely be underground to protect humans from solar and cosmic radiation. The moon’s surface has high levels of radiation, which can cause health issues like cancer, cataracts, and central nervous system diseases. Underground habitats should be at least 80 centimeters (2.5 feet) below the surface to protect people from harmful particles

Some say the best location for a moon base is at the south pole, where there’s a gentle slope and a relatively large water supply. NASA plans to build a permanent base at the south pole by the 2030s, where astronauts can stay for extended visits

Almost certainly underground. Anywhere you wanted to stay on thre moon for long would have to be heavily shielded from solar and cosmic radiation, and that requires lots of dense mass

Could underground cities be build like modern cities

Yes, underground cities can be built like modern cities, but they require careful design to address issues like water, sound, vegetation, and light. Underground cities can be more defensible and thermally stable than above-ground cities, and they can reduce energy consumption by more than 23%. However, they also have some disadvantages, including: 

• Lighting: Lighting is more expensive because there’s no daylight 
• Supply lines: It’s harder to access resources from the surface, like food and firewood 
• Indoor environmental quality: Underground cities may not have the same indoor environmental quality as above-ground cities 

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