per Brad Plumer, Bill Clinton says that Area 51 has no aliens and who know what happened at Roswell….
CLINTON: (Laughing and blushing) Well I don’t know if you all heard this, but, there was actually, when I was president in my second term, there was an anniversary observance of Roswell. Remember that? People came to Roswell, New Mexico from all over the world. And there was also a site in Nevada where people were convinced that the government had buried a UFO and perhaps an alien deep underground because we wouldn’t allow anybody to go there. And uhm