Comprising a total of eight tight hairpin turns as it meanders down a hill in San Francisco, Lombard Street is the world's most crooked road. While many roads twist and turn often, only a 400-m (1/4-mile) long section of Lombard Street, as it descends a 27% incline, can claim so many hairpin turns in such a short distance - a total of 1,440 degrees twisted and turned in only 400 m. Only allowing one-way traffic down the hill, Lombard Street is paved with red bricks and possesses a mandatory 5-mile-an-hour speed limit. The road is famous, having featured in films such as Alfred Hitchcock's Vertigo. The road is a principal route and is co-signed as US Route 101