Dr. Edgar Mitchell, a member of the Apollo 14 moon mission who, along with Alan Shepard, holds the record for the longest moon walk,  stated in a radio interview that extraterrestrials have visited Earth on several occasions and that these visits have been covered up by the world's governments.

He claims to have been briefed by NASA on these alien visitors and that the world-wide government cover up has been going on for more than six decades. A few quotes from the interview:

"I happen to have been privileged enough to be in on the fact that we've been visited on this planet and the UFO phenomena is real,"

"I've been in military and intelligence circles, who know that beneath the surface of what has been public knowledge, yes - we have been visited. Reading the papers recently, it's been happening quite a bit."

He claims that our technology is "not nearly as sophisticated" as theirs and "had they been hostile we would be been gone by now".

NASA has flatly denied these allegations.

I have a lot of respect for the man, but wonder if, at the age of 77, he isn't a bit off his rocker or just seeking out a bit of publicity for himself. While I acknowledge the high probability that intelligent life exists elsewhere in our universe, I think there's a very low probability that all of the major governments of the world could keep such a thing secret for so long.

One can find numerous reports regarding his radio interview on the web. If nothing else, it does make for some entertaining reading.