Mythbusters: Season 3, Episode 22

3 - 22: Border Slingshot

The MythBusters take a pot shot at an ancient Chinese text that alludes to a subterranean sonar system that could apparently detect and intercept an invasion from below. And watch Adam and Jamie test out a myth that millions of hungry Americans invoke every day — if it's been on the floor for less than five seconds, is it really safe to eat?