© Getty Images

Grand Central Station secret underground room -

A hidden power station, known as M42, lurks beneath New York City's renowned station. This bunker, occupying 22,000 sq ft and situated 10 floors beneath the surface, was officially recognized in the 1980s but remains absent from official records.

© Getty Images

Grand Central Station secret underground room -

Its original converters played a crucial but secret part in World War II by supplying power to a significant portion of the New York Central Railroad, which the Germans aimed to disrupt along the East Coast.

© Getty Images

Secret afghan prisons -

In 2008, the Obama administration declared the eradication of all Abu Ghraib-style prisons, or "black sites," in Afghanistan.

© Getty Images

Journalist Kimberly Dozier -

In 2011, journalist Kimberly Dozier (pictured) revealed that the Joint Special Operations Command concealed 20 prisons where Afghan individuals continued to suffer abuse and torture at the hands of guards.

© Getty Images

Operation Northwoods -

The US government staged a simulated terrorist attack on American civilians in 1962, aiming to create a pretext for a military intervention in Cuba and deceive the American public into backing it.

© Getty Images

Operation Northwoods -

The operation has caused many Americans to think that the US government might be responsible for other attacks in the US.

© Getty Images

Assassination attempts on Fidel Castro -

The CIA’s efforts to kill the former Cuban ruler included some bizarre plots. In one of these attempts, the agency poisoned a box of Castro’s favorite cigars in 1960, but they never reached El Comandante. No one knows what happened to the cigar box.

© Getty Images

Assassination attempts on Fidel Castro -

The CIA made another unsuccessful effort by enlisting two notorious criminals from the FBI's most wanted list to eliminate Castro. These individuals were Sam Giancana, the leader of the Chicago mob, and Santos Trafficante, who oversaw the mob’s activities in Cuba.

© Getty Images

Area 51 -

Known for its mysterious nature, this Air Force facility located in Nevada was reportedly used as a covert flying area during the 1960s to conduct experiments with reconnaissance aircraft. The official names attributed to the facility are Homey Airport (ICAO: KXTA) and Groom Lake. However, the term "Area 51" was mentioned in a CIA document from the time of the Vietnam War.

© Getty Images

Area 51 -

There are those who think the base continues to fulfill a similar purpose, while others believe it also serves as a facility for undisclosed weaponry.

© Getty Images

Area 51 -

The facility's secretive nature transformed it into a well-known reference in alien-themed pop culture. Conspiracy theorists believe that Area 51 hides the truth about alien life on Earth. 

© Getty Images

Area... 52? -

Situated approximately 70 miles northwest of Area 51, the Tonopah Test Range (TTR) in Nevada has sparked curiosity among conspiracy theorists due to its utilization of experimental and classified aircraft.

© Getty Images

Area... 52? -

In contrast to its neighboring area, the test range has managed to steer clear of any connection to alien phenomena, therefore the enigma surrounding the location primarily revolves around military and governmental affairs. Currently, the site is utilized for storing nuclear weapons, conducting reliability tests, undertaking research, as well as developing fusing and firing systems.

© Getty Images

MK Ultra -

The MKUltra project, conducted by the CIA, was an extremely disturbing initiative consisting of illicit tests on individuals. Its aim was to discover and advance drugs and methods that could manipulate the mind to extract confessions and other information during interrogations.

© Getty Images

MK Ultra -

Despite sounding like a conspiracy theory, the program was indeed genuine. It started in 1953 and persisted until the 1970s. However, some people believe that the program is ongoing. Tragically, the experiments led to the deaths of at least two Americans.

© Public Domain

The Dugway Proving Grounds -

Located about 85 mi southwest of Salt Lake City, this US Army facility was established in 1942 to test biological and chemical weapons.

© Getty Images

The Dugway Proving Grounds -

The president of Utah UFO Hunters, Dave Rosenfeld, highlighted that the testing of hazardous biological and chemical weapons in a highly confidential facility would inevitably draw attention. In 2004, the Deseret News stated that "UFOs have been seen and reported in the area in and around Dugway”, Dave Rosenfeld, said.

© Getty Images

Area 6 -

The one-mile runway in the Nevada desert's Yucca Flat could potentially serve as a testing site for sensors on a top-secret fleet of drones.

© Getty Images

Area 6 -

Situated approximately 12 miles northeast of the notorious Area 51, limited information is available about the site. However, the Yucca Airstrip on the premises is used by both the Department of Defense and the Department of Homeland Security.

© Getty Images

The Boeing X-37B -

The reusable unmanned spacecraft, also called the Orbital Test Vehicle (OTV), originated as a NASA project in 1999 before being handed over to the US Department of Defense in 2004. However, its purpose and current application is unknown.

© Getty Images

The Boeing X-37B -

According to an article by Tom Burghardt for Space Daily in May 2010, there were claims that the Boeing was being employed either as a spy satellite or for transporting weapons from space, although these allegations were rejected by the Pentagon. Additional rumors suggest that the X-37B is being used to target spacecraft belonging to other countries.

© Getty Images

The USS Jimmy Carter -

The nuclear-powered submarine, launched in 2004, is reportedly engaged in a covert operation to observe North Korea.

© Getty Images

The USS Jimmy Carter -

According to a 2017 report by the Washington Examiner, it was stated that the submarine was displaying a Jolly Roger flag. The article suggested that the machinery on board might have been involved in an espionage mission.

© Getty Images

Utah Data Center -

Known as the Intelligence Community Comprehensive National Cybersecurity Initiative Data Center, this data storage facility in the Utah desert allegedly monitors our online and phone activities on a massive scale.

© Getty Images

Utah Data Center -

The website clearly declares its motto: "if you have nothing to hide, you have nothing to fear."

© Getty Images

FBI’s blacklist -

During post-World War II America, the FBI regularly added artists and celebrities to its watch list as a means to counteract communism and other sentiments opposing the government and its wars.

© Getty Images

FBI’s blacklist -

The list had names like John Lennon, Bud Abbott, Lou Costello, and Charlie Chaplin.

© Getty Images

Reagan’s HAARP Initiative -

The High-Frequency Active Auroral Research Program (HAARP), authorized during the Reagan administration, is a program in Alaska aimed at studying the ionosphere and exploring advancements in radio communications and surveillance. However, it has generated various theories.

© Getty Images

Reagan’s HAARP Initiative -

There were rumors circulating about strange activities taking place at a base in Poker Flats (pictured). Some alleged that mind-control experiments were being conducted, while others believed that the Reagan Administration was working on technology to manipulate the climate and weather. The base supposedly shut down a few years ago. 

Sources: (Washington Examiner) (NSA) (Wired)

See also: The world's most notorious spies

© Getty Images