The courtroom is the first thing that gets you. In 1950 a U.S. Senate committee chasing organized crime held one of its hearings in this room, on the second floor of the downtown federal courthouse, and the room is still here. The Mob Museum, officially the National Museum of Organized Crime and Law Enforcement, fills the whole building. It opened on February 14, 2012, the 83rd anniversary of the St. Valentine's Day Massacre. The date was not an accident.
The building is the first exhibit
The Mob Museum sits in the 1933 Las Vegas Post Office and Courthouse on Stewart Avenue, a few blocks from Fremont Street. The federal government sold the building to the city in 2000 for one dollar, and the museum idea came from Oscar Goodman, then the mayor and before that a defense lawyer for reputed mobsters. Few cities could tell this story in their own courthouse. Las Vegas can.

Where: Stewart Avenue and Third Street, Downtown Las Vegas. Highlights: the Massacre wall, the Kefauver courtroom, the Crime Lab, The Underground. Best for: history fans, true-crime fans and anyone who wants Las Vegas before the megaresorts.
Inside: the wall, the courtroom and the simulators
The museum spreads nearly 20,000 square feet of exhibits across four floors. The piece people stop for is the brick wall from the Chicago garage where seven men were shot on February 14, 1929, rebuilt here brick by brick. The courtroom tells the Senate hearings story from the bench. Then the tone turns to the other side: a Crime Lab on forensic science, and a firearm training simulator that puts you in a police officer's split-second decision. It's harder than it looks. Real wiretap recordings and the Las Vegas chapters fill the rest.
The Underground: moonshine in the basement
The basement is a working Prohibition-style speakeasy and distillery called The Underground, open since April 2018. It makes its own 100-proof corn moonshine in a custom-built pot still. Museum visitors reach it from inside the building. It's the right ending.
Before you go
There's a paid lot beside the building for drivers, and from the Strip a rideshare is simplest. The Mob Museum pairs well with an evening downtown: our Neon Museum guide covers the sign boneyard a short ride north, and our downtown Segway tours roll through the same streets. Four floors add up fast.
The moment worth the ticket
Stand in front of the Massacre wall long enough and the bullet damage stops looking like a prop. That's the moment. Afterwards, Fremont Street's canopy is a short walk south, so the museum slots neatly into the afternoon before a downtown night.