Anyway, the idea that you can keep a secret that 100,000+ people are in on is just silly. If you really want to know, use sonar to look at the mass graves. Still the allure of conspiracy theories is huge. So it’s easy for people to ignore evidence that does not support their pet theory.
PS: My favorite theory is idea that UFO's where created by the US Air force to misdirect the Russians when people in the middle of the country started seeing strange objects in the sky they would see reports from the US of the same thing. The advantage of this theory is it would take a small number of people to create, and those in the know would have little reason to tell the truth thinking it's a good joke.