© Getty Images

Hidden chamber discovered beneath Grand Central Station -

New York City's most famous station conceals a covert power station that is absent from official documents. Dubbed M42, the concealed 22,000 sq ft bunker positioned ten floors beneath the main level was officially acknowledged in the 1980s.

© Getty Images

Hidden chamber discovered beneath Grand Central Station -

During World War II, the original converters played a significant and hidden role in the New York Central Railroad's operations, which were targeted by the Germans in their attempts to disrupt rail transportation along the east coast.

© Getty Images

Area 51 -

Often surrounded by secrecy, this facility of the United States Air Force in Nevada was reportedly utilized as a covert flight zone during the 1960s to conduct reconnaissance aircraft tests. The official designations for this facility are Homey Airport (ICAO: KXTA) and Groom Lake; however, during the Vietnam War, it was referred to as Area 51 in a CIA document.

© Getty Images

Area 51 -

There is a belief that the base continues to serve a comparable purpose, while another belief suggests that the location is additionally utilized for storing classified weaponry.

© Getty Images

Area 51 -

The facility's secrecy has made it a popular reference in alien pop culture.

© Getty Images

Area 51 -

Many think that Area 51 is where the US keeps captured aliens and their flying objects. The US government denies any such theories.

© Getty Images

Area 51 -

Barack Obama was the first US President to publicly mention the site.  

© Getty Images

Area... 52? -

The Tonopah Test Range (TTR) in Nevada, situated approximately 70 miles northwest of Area 51, has captivated conspiracy theorists due to its utilization of experimental and classified aircraft.

© Getty Images

The Tonopah Test Range (TTR) -

In contrast to the adjacent area, the test range has not been associated with activities involving beings from outer space. Therefore, the enigma surrounding this location is solely related to military and government matters. At present, the site is utilized for storing nuclear weapons as well as conducting tests to assess their dependability, perform research, and advance fusing and firing systems.

© Getty Images

The Tonopah Test Range (TTR) -

Veterans who worked at Tonopah in later years seek compensation, alleging that exposure to lingering radiation has resulted in health issues. They claim the federal government was aware of contaminated areas at the Nevada Test and Training Range (NTTR) but failed to protect military and civilian personnel.

© Getty Images

The Dugway Proving Grounds -

This US Army facility, situated approximately 85 miles southwest of Salt Lake City, was founded in 1942 for the purpose of testing biological and chemical weapons.

© Getty Images

The Dugway Proving Grounds -

Employees at this facility deal with some of the most lethal and hazardous biological and chemical agents on the planet.

© Getty Images

The Dugway Proving Grounds -

The experimentation with hazardous biological and chemical weapons within an ultra-secret facility is sure to draw interest. In 2004, the Deseret News stated that Dave Rosenfeld, the president of Utah UFO Hunters, claimed,  “UFOs have been seen and reported in the area in and around Dugway.”

© Getty Images

MK Ultra -

The MKUltra, carried out by the CIA, was a highly alarming program involving illegal experiments on people. It aimed to discover drugs and methods for obtaining confessions and extracting information during interrogations by means of mind control techniques.

© Getty Images

MK Ultra -

Despite sounding like a conspiracy theory, the program was indeed factual. It commenced in 1953 and persisted until the 1970s, although some assert that it may still be ongoing. Tragically, the experiments claimed the lives of two Americans.

© Public Domain

Area 6 -

Situated in the Yucca Flat within the Nevada desert, an estimated base for evaluating sensors on a classified squadron of drones is a one-mile landing strip.

© Getty Images

Area 6 -

Situated approximately 12 miles northeast of the notorious Area 51, very little information is available about this site. However, the Yucca Airstrip located on-site is utilized by both the Department of Defense and the Department of Homeland Security.

© Getty Images

Operation Northwoods -

The US government carried out an operation in 1962, which involved fabricating a terrorist attack against American civilians. This deceptive act was aimed at justifying a US military intervention in Cuba and manipulating Americans into supporting it.

© Getty Images

Operation Northwoods -

The operation has caused many Americans to suspect that the US government might be responsible for other attacks within the country.

© Getty Images

Assassination attempts on Fidel Castro -

The CIA made unusual attempts to eliminate the ex-Cuban leader, which involved peculiar schemes. In a particular endeavor in 1960, the agency poisoned a box of Castro's cherished cigars; however, they never reached El Comandante. The whereabouts of the cigar box remain unknown.

© Getty Images

Assassination attempts on Fidel Castro -

In another unsuccessful try, the CIA enlisted 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 operations in Cuba.

© Getty Images

The Boeing X-37B -

The reusable unmanned spacecraft, also called the Orbital Test Vehicle (OTV), originated as a NASA project in 1999 and was later transferred to the US Department of Defense in 2004. However, there is limited awareness regarding its purpose or current utilization.

© Getty Images

The Boeing X-37B -

According to a 2010 Space Daily article by Tom Burghardt, there were allegations that the Boeing was being used either as a spy satellite or to transport weapons from space. However, the Pentagon denied these claims. Other rumors suggest X-37B was intended for sabotaging other countries' spacecraft.

© Getty Images

The Boeing X-37B -

Continuing NASA's experiments with space technology, the X-37B Orbital Test Vehicle (OTV) set a new endurance record by spending 908 days in orbit before landing at NASA's Kennedy Space Center in Florida. This surpasses its previous record of 780 days in orbit.

© Getty Images

The USS Jimmy Carter -

The USS Jimmy Carter is considered the most secretive submarine in the U.S. Navy, designed specifically for Seabed Warfare and undisclosed missions deep underwater. 

© Getty Images

The USS Jimmy Carter -

Initiated in 2004, this nuclear-powered submarine is rumored to be engaged in a covert mission to conduct espionage on North Korea.

© Getty Images

The USS Jimmy Carter -

The Washington Examiner reported in 2017 that the submarine was displaying a Jolly Roger and suggested that its machinery was involved in possible espionage activities.

© Getty Images

Utah Data Center -

The data center situated in the Utah desert, known as the Intelligence Community Comprehensive National Cybersecurity Initiative Data Center, is said to monitor all online and phone activities.

© Getty Images

Utah Data Center -

Its immense scale, covering nearly 140,000 square meters, makes it one of the largest data centers in the US.

© Getty Images

Utah Data Center -

The website clearly displays the 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 added artists to its watch list as a means to suppress communism and other anti-government and anti-war sentiments.

© Getty Images

FBI’s blacklist -

The list contained names such as John Lennon, Bud Abbott, Lou Costello, and Charlie Chaplin.

© Getty Images

Secret afghan prisons -

In 2008, during the Obama administration, it was stated that all Abu Ghraib-style prisons or "black sites" had been eradicated in Afghanistan.

© Getty Images

Journalist Kimberly Dozier -

In 2011, journalist Kimberly Dozier discovered that the Joint Special Operations Command concealed 20 prisons where Afghans continued to endure mistreatment and torture by the guards.

© Getty Images

Reagan’s HAARP Initiative -

The Reagan administration sanctioned the High-Frequency Active Auroral Research Program (HAARP), an ionospheric research initiative based in Alaska, aimed at studying the ionosphere and exploring potential advancements in radio communications and surveillance technology. However, the program has given rise to various obscure theories and speculations.

© Getty Images

Reagan’s HAARP Initiative -

The High-frequency Active Auroral Research Program (HAARP) is ongoing, involving universities and led by the University of Alaska Fairbanks. Experiments include generating artificial airglow and studying electromagnetic waves.

© Getty Images

Reagan’s HAARP Initiative -

One rumor suggested that mind-control experiments were being conducted, while others believed that the Reagan Administration was developing technology to manipulate the climate and weather. 

Sources: (Washington Examiner) (NSA) (Wired) (Naval News) (Business Insider)

See also: What we know about Area 51, the top-secret military base

© Getty Images