The history of Las Vegas as a city has long been associated with the Mafia, and most of the original hotels were built with mob money, so it's no surprise that downtown Las Vegas has a fascinating collection of mob memorabilia on display. The three-story Mob Museum tracks the history of the American Mafia from its origins in Chicago and New York through its expansion west. Even those who have never been fascinated by the mob will find a painstakingly-executed museum and local treasure. Tickets are $14 to $20.