Video compliments of the Travel Channel

Sin City didn't earn its nickname by always playing nice. What started out as a Mormon settlement shifted into a shadowy playground for the mob (marked by business deals and bloody infighting) before morphing, again, into the glitzy and glamorous modern Las Vegas.

At the beginning of the 20th century, the city's red-light district (known as Block 16) was a naughty nabe of gambling, boozing and prostitution (despite laws at the time that restricted all three). But it was mainly frequented by locals and traveling cowboys. Smelling an opportunity, New York organized crime bosses Meyer Lansky and Frank Costello sent the infamous Bugsy Siegel in 1937.

Known as "the man who made Las Vegas," Siegel schmoozed and intimidated his way into Vegas's inner circles and, with the mob's significant backing, opened the first Las Vegas gambling palace, the Flamingo, in 1946. In 1939 Siegel and three other mobsters killed Harry "Big Greenie" Greenberg, when they discovered he was a police informant. Siegel was tried and acquitted of the murders, though in 1947 he met a similar fate when Lansky, his friend and mob boss, ordered a hit on him (or so it is widely assumed), because the Flamingo Hotel still wasn't turning a profit. Siegel was shot several times in his own home and his murder never solved.

By the 1950s, the Chicago mob had joined the New York mob in Vegas, opening the Desert Inn, the Riviera and the Stardust (the headquarters to the Rat Pack, which included Frank Sinatra, Dean Martin and Sammy Davis, Jr.). The mob's power in Sin City came to a close when state legislation allowed private corporations to own casinos. The mob made millions selling their gambling palaces, though its presence lingered. In 1979, the FBI connected Kansas City's Civella mob family to the Tropicana and raided the hotel on Valentine's Day. Convictions were widespread and organized crime's control of the Strip was finally broken.