Reports of UFO sightings are a dime a dozen in the U.S. and almost always accompanied by stories of abduction or a threat of an invasion. But the interest with these things extend far beyond the American soil -- sightings are global. And according to Luis Elizondo, former head of a top-secret U.S. government agency tasked with investigating UFOs, we should take them seriously.

Many people would automatically think a UFO is an alien spacecraft. However, this isn't always the case, according to Elizondo in an interview with Live Science. UFOs, for all we know, is a piece of tech deployed by hostile human source, so we can't really rule out the potential that these mysterious flying objects pose no threat.

Elizondo believes that the potential threats posed by UFOs should be a matter discussed by world leaders.

"I think we're at the point now where we're beyond reasonable doubt that these things exist," Elizondo said. "We know they're there - we have some of the greatest technology in the world that has confirmed their existence."

However, what we're all entirely unsure about is the origins of these objects, what they can do, what their purpose is. These are the things that Elizondo and other experts will discuss in the History Channel series "Unidentified: Inside America's UFO Investigation" Season 2.

Elizondo was the head of Pentagon's Advanced Aerospace Threat Identification Program (AATIP), which was founded in 2007. He has since left Pentagon and is now a director of To the Stars Academy of Arts and Science, a private agency pursuing evidence of UFOs.

In the show, Elizondo and former Deputy Assistant Secretary of Defense and Intelligence Chris Mellon gather eyewitness accounts of UFO sightings and piece clues in an attempt to debunk the unexplainable.

UFOs, despite the doubts surrounding these objects, have long been studied by the U.S. government. All data from 1952 to 1969 pertaining to these unexplainable phenomena are recorded in the Air Force's Project Blue Book and. The responsibility was later passed to the National Investigations Committee on Aerial Phenomena (NICAP).

In Project Blue Book alone, more than 12,000 reports of UFO sightings have been recorded. Though most accounts turned out to be a misidentification of stars, clouds, weather balloons, or aircraft, 700 incidents were reportedly unsolved.

Because of the stigma and government secrecy surrounding UFOs, sightings are easily dismissed as hallucinations or hoaxes. However, Elizondo believes that as long as we remain clueless to the origins of these objects, it would be unwise not to take them seriously.