It all started in 1947.

On June 24, Kenneth Arnold, a private pilot, sighted nine “flying saucers” near Mount Rainier on his way to an air show in Oregon. At first, he thought that it was a reflection of the sun coming from another aircraft. Later, he aimed to define the “unidentified flying objects (UFO)” that may be real and could pose a national security threat.

After Kenneth’s “saucer skipped over water,” his definition of their flight motion, the world started to believe that aliens travel all around the world in flying saucers. Reportedly, by the end of 1947, nearly 1,000 domestic UFO sightings had been reported. Soon, the number of sightings became too many for the U.S. Air Force to ignore.

In 1954, during a golfing vacation to Palm Springs, U.S. then-President Dwight Eisenhower visited a dentist at night in Edwards Air Force Base. When the press found out that the president had a midnight visit to the “dentist,” many agencies claimed that the incident was suspicious and he had lied that night.

The rumors claimed that Eisenhower had met with aliens instead. In this alleged meeting, aliens referred to as “Nordics,” who were disguised in “human form,” and Eisenhower made a deal, enabling them to abduct humans for their extraterrestrial experiments on the condition they were returned unharmed. A few months after this “encounter,” a mystic appeared and claimed that he was at the base that night and witnessed Eisenhower interacting with aliens and flying saucers.

Eisenhower quickly became the first U.S. president believed to have interacted with extraterrestrials.

Likewise, many alien encounters are listed in the U.S. government program “Project Blue Book” tasked to inspect UFOs from 1948 to 1969. Yet, the project was concluded as no aliens were uncovered and they were determined to not pose a threat to U.S. national security.

Area 51, which the CIA officially acknowledged as a secret military base near Las Vegas, has been another conspiracy theory cradle for decades. Many people thought the U.S. government stored alien bodies in the location. Yet, the U.S. government announced that the need for secrecy was to hide information from the Soviets rather than to cover up extraterrestrial bodies.

In 1997, Arizona residents reported another alien encounter in the sky after they saw flying objects near Phoenix. Years later, Arizona’s governor, also a former Air Force officer, confirmed the report, citing his experience as well.

The year 2007 marks the official government efforts to establish UFO studies with the Advanced Aerospace Threat Identification Program.

In 2010, seven former Air Force officers detailed their experiences with aliens as they were flying over nuclear weapon facilities.

The Obama administration received two petitions asking that the U.S. government formally acknowledge extraterrestrials’ existence and their numerous visits to Earth. The White House, however, replied by saying there was no concrete evidence to prove their existence and that no life existed outside the planet.

Last month, the Pentagon promised to take encounters with UFOs seriously in the first public congressional hearing on the matter in five decades. On Thursday, NASA announced that they will be recruiting a new team to get to the bottom of this phenomenon. Somehow, this matter has finally gained high-level attention from United States Congress after 50 years.

The alien investigation, which used to be laughed at, seems to be getting more serious now.