If you've ever wondered how cable cars work, this nifty museum explains (and demonstrates) it all. Yes, this is a museum, but the Cable Car Museum is no stuffed shirt. It's the living powerhouse, repair shop, and storage place of the cable car system and is in full operation. Built for the Ferries and Cliff House Railway in 1887, the building underwent an $18-million reconstruction to restore its original gaslight-era look, install an amazing spectators' gallery, and add a museum of San Francisco transit history.

The exposed machinery, which pulls the cables under San Francisco's streets, looks like a Rube Goldberg invention. Stand in the mezzanine gallery and become mesmerized by the massive groaning and vibrating winches as they thread the cable that hauls the cars through a huge figure-eight and back into the system using slack-absorbing tension wheels. For a better view, move to the lower-level viewing room, where you can see the massive pulleys and gears operating underground.

Also on display here is one of the first grip cars developed by Andrew S. Hallidie, operated for the first time on Clay Street on August 2, 1873. Other displays include an antique grip car and trailer that operated on Pacific Avenue until 1929, and dozens of exact-scale models of cars used on the various city lines. There's also a shop where you can buy a variety of cable car gifts. You can see the whole museum in about 45 minutes.