30 Hidden Underground Cities in America

30 Hidden Underground Cities in America

Secret Underground Places in America

There are numerous secret underground places in America, hidden from the public, including Raven Rock, a secret underground city carved out by the US government as a potential refuge in case of nuclear war. This self-sufficient base features offices, amenities, and protection from blasts.

Historic Underground Areas

Atlanta’s historic downtown area and New York City’s hidden underground world are notable examples. Atlanta’s area started as a commercial district in the 1800s and was rebuilt in the 1960s as a music and bar scene. New York City has a secret world of tunnels and hidden spaces, including an old subway station with stained glass and mosaics, and underground infrastructure such as pipes, subway tracks, and mail tubes.

Notable Underground Complexes

  • The world’s oldest subway tunnel is in Brooklyn’s Atlantic Avenue, built in 1844 and rediscovered in 1980.
  • The Perma frost tunnel in Alaska, used to study permafrost.
  • A proposed underground city in Manhattan, designed as a safe haven during a nuclear attack.

Planned and Completed Underground Cities

A planned underground city, nicknamed “mini Manhattan,” was designed to hold 1 million people with all necessary resources, but it never became a reality. However, similar projects were completed, such as:

  • The SubTropolis in Kansas City, a 55 million square foot underground business complex.
  • The Seattle Underground, a hidden city beneath Seattle’s streets that was created after a fire in 1889.

Underground Spaces and Attractions

Underground spaces were used by people until they were closed in 1907 to prevent illegal activities, but later became a tourist attraction. Other notable underground spaces and attractions include:

  • The PATH system in Toronto, a huge underground walkway that started in the 1920s.
  • The Greenbrier bunker in West Virginia, a secret underground facility beneath a luxury hotel, built during the Cold War.
  • Nashville, Tennessee’s hidden tunnels with stories of smuggling, hidden railroads, and city expansion.
  • The Blue Grass Underground, a concert venue 333 ft underground in a cave, known for its natural acoustics and unique live music performances.

Hidden Underground Attractions

Other hidden underground attractions include:

  • The catacombs beneath Indianapolis City Market.
  • Los Angeles’ 11-mile network of prohibition tunnels.
  • The Crypt of Civilization in Georgia, which offer unique experiences and glimpses into history through tours and exploration.

Secure Facilities and Time Capsules

The Cheyenne Mountain Complex, a giant bunker in Colorado built during the Cold War, is a highly secure facility with its own power, water, and food supply. A time capsule sealed in 1940 at Oglethorpe University will remain closed until 8113.

Underground Tunnels and Systems

Denver has a hidden tunnel under the state capital that holds the steam heating system and storage, including marble for repairs, as well as empty vaults. Washington DC has a vastly used underground system, unknown to many outside of government, which connects government buildings and subway stations, and features restaurants, food courts, and shops.

Unique Underground Locations

Other unique underground locations include:

  • The Louisville Mega Cavern, a huge underground space used for storage, events, and an underground bike park.
  • The Old North Church Crypt in Boston, which has over 1100 burials and is famous for its role in the American Revolution.
  • The Cavern Suite in the Grand Canyon Caverns, a hotel room 220 feet underground known for being the darkest and quietest room in the world.
  • Underground tunnels and spaces in Montana and California, including old steam tunnels and Underground Gardens, that showcase historical uses and offer a glimpse into the past.

Historic Underground Areas and Ghost Towns

Ellenwood, Kansas, has a ghost town under its streets with old saloons, shops, and bathhouses that can be visited. Old Sacramento’s underground tunnels and basements, built in the 1860s to protect the city from floods, now offer tours of the historic area, including old items and hidden brothels.

Underground Structures and Mansions

Monuma Castle, a 900-year-old mud and rock home built into the side of a cliff in Arizona, and a Las Vegas underground mansion, built 26 feet underground in 1978 as a survival shelter with amenities like a garden, swimming pool, and mini golf course, are two unique underground structures.


Key Vocabulary

Term Definition Example Usage
Raven Rock A secret underground city in the US, built as a potential refuge in case of nuclear war. The US government built Raven Rock as a self-sufficient base with offices and amenities.
Permafrost Tunnel A tunnel used to study permafrost, located in Alaska. Scientists use the Permafrost Tunnel to research the effects of climate change on permafrost.
SubTropolis A 55 million square foot underground business complex in Kansas City. The SubTropolis is a unique example of an underground city, with various businesses and amenities.
Seattle Underground A hidden city beneath Seattle’s streets, created after a fire in 1889. The Seattle Underground is now a popular tourist attraction, offering tours of the historic area.
PATH System A huge underground walkway in Toronto, started in the 1920s. The PATH System is a convenient way for pedestrians to navigate the city, with shops and restaurants along the way.
Greenbrier Bunker A secret underground facility beneath a luxury hotel in West Virginia, built during the Cold War. The Greenbrier Bunker was designed as a safe haven for government officials in case of a nuclear attack.
Cheyenne Mountain Complex A highly secure facility in Colorado, built during the Cold War, with its own power, water, and food supply. The Cheyenne Mountain Complex is a self-sufficient base, capable of withstanding a nuclear attack.
Time Capsule A sealed container holding artifacts and information, to be opened at a future date. A time capsule was sealed in 1940 at Oglethorpe University, to remain closed until 8113.
Underground Tunnels Hidden passageways beneath cities, often used for infrastructure, transportation, or secret activities. Denver has a hidden tunnel under the state capital, holding the steam heating system and storage.
Ghost Town An abandoned town or city, often with remnants of past inhabitants and activities. Ellenwood, Kansas, has a ghost town under its streets, with old saloons, shops, and bathhouses.
Underground Mansion A luxurious residence built underground, often with advanced security and amenities. A Las Vegas underground mansion was built 26 feet underground in 1978, with a garden, swimming pool, and mini golf course.

Watch The Video

30 Hidden Underground Cities in America

Vocabulary Quiz

1. Which word means ‘a place that is safe from harm or danger’?

A) Refuge
B) Infrastructure
C) Haven
D) Permafrost

2. What is the term for ‘a layer of soil and rock that remains frozen throughout the year’?

A) Subway
B) Tunnel
C) Permafrost
D) Mosaic

3. Which word means ‘a system of pipes, tracks, and other structures that support a city or building’?

A) Amenities
B) Infrastructure
C) Subway
D) Mail tubes

4. What is the term for ‘a self-contained and isolated place that has all the necessary resources for survival’?

A) Self-sufficient base
B) Hidden world
C) Underground city
D) Luxury hotel

5. Which word means ‘a place or structure that is built or located underground, often for protection or secrecy’?

A) Bunker
B) Mansion
C) Castle
D) Subway station

Answer Key:

1. C
2. C
3. B
4. A
5. A


Grammar Focus

Grammar Focus: The Use of the Past Perfect Tense

The past perfect tense is used to describe an action that occurred before another action in the past. It is formed using the auxiliary verb “had” + the past participle of the main verb. For example, in the text, it is mentioned that “Atlanta’s area started as a commercial district in the 1800s and was rebuilt in the 1960s as a music and bar scene.” Here, the past perfect tense is not explicitly used, but we can infer the use of the past perfect tense in a sentence like “The area had been a commercial district before it was rebuilt.” This tense is crucial in understanding the sequence of events and how they relate to each other. Another example from the text is “The world’s oldest subway tunnel is in Brooklyn’s Atlantic Avenue, built in 1844 and rediscovered in 1980,” which implies “The tunnel had been built in 1844 before it was rediscovered in 1980.”

Grammar Quiz:

1. By the time the city was rebuilt, the old district ____________________ for over a century.

  • A) has been used
  • B) was used
  • C) had been used
  • D) is used

2. The secret underground world in New York City ____________________ by the time the new subway system was built.

  • A) had been discovered
  • B) was discovered
  • C) is discovered
  • D) discovers

3. Before the fire in 1889, the area that is now the Seattle Underground ____________________ as a normal part of the city.

  • A) was used
  • B) has been used
  • C) had been used
  • D) is used

4. The SubTropolis in Kansas City ____________________ by the time it became a major business complex.

  • A) had been planned
  • B) was planned
  • C) is planned
  • D) plans

5. By the time the Cold War ended, the Cheyenne Mountain Complex ____________________ as a secure facility for decades.

  • A) had been used
  • B) was used
  • C) is used
  • D) uses

Answer Key:

  • 1. C) had been used
  • 2. A) had been discovered
  • 3. C) had been used
  • 4. A) had been planned
  • 5. A) had been used