Lyon's traboules: the hidden passageways

Lyon's old silk-trade neighborhoods, Vieux Lyon and the Croix-Rousse hill, are threaded with "traboules," covered passages that cut through buildings and courtyards. Dozens are open to the public during the day; look for a small plaque by the door, push it open, and walk through. They're residents' homes, so keep your voice down and close the doors behind you. The tourist office publishes a map, and the best ones hide Renaissance staircases you'd never guess from the street.