Welcome to Las Vegas, America's Sin City, where billions of dollars are lost and made every year on our national vices. In order to protect their cash, casinos have made security the highest priority. From underground vaults to secret surveillance nerve centers, we'll uncover how the latest technology beats the cheaters. But Vegas wasn't always this high-tech. We'll show how a massive engineering feat transformed the city from a barren desert into a mobster metropolis where thieves ran the show from underground tunnels dating back to Prohibition. And just when it looked like all the thugs were behind bars and the city would fall off the map for good, Vegas became the come back kid. It's the only city in the world where you can be in Egypt one moment and Italy the next, thanks to a secret underground that allows the show to get bigger and better every time.