What was once a crackpot conversation among mocked believers has now gone mainstream. Speaking to NPR, former Nevada Sen. Harry Reid explained why the U.S. military has been hiding the sightings of UFOs for 70 years.

"The reason we didn't hear more about them is because the military kept it all secret until very recently," Reid explained. "We don't know what they are, but we don't know what they aren't either. We just don't know. That's the way I look at it. We know now, without any hesitancy that they exist."

When asked why the U.S. government would hide what they've seen about UFOs, Reid said that it's possible people in authority feel "it could be damaging to the security of our country."

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