Among San Francisco's most photographed tourist attractions, the 1000 block of Lombard Street boasts eight switchbacks in its one-block descent from Hyde to Leavenworth. The block's natural 27 percent grade was gentled to 16 percent in 1922, when cobblestones were used to pave the street. Today, roughly three-quarters of a million cars negotiate the hairpin turns each year, descending through banks of hydrangeas.Climb the stairs flanking the curves to Hyde Street, where views extend north and east. From here, cable cars coast down to Ghirardelli Square and the Hyde Street Pier against a backdrop of Alcatraz and Angel Island.