UFO expert Nick Pope urges public not to attend Area 51 event

A UFO expert is urging people not to attend the viral Facebook event 'Storm Area 51' in Nevada on September 20. Small towns in the US state are bracing for an influx of alien enthusiasts, with over 2 million people declaring online they are going to go. But why does Area 51 mean so much to people who want to believe in alien life?