3001 Connecticut Ave NW; closest Metro stop is Woodley Park-Zoo. Buildings open daily May to mid-Sept 10am6pm; rest of year 10am4.30pm. Grounds daily May to mid-Sept 6am8pm; rest of year 6am6pm. Admission free. www.si.edu/natzooo/
Few people realize that the National Zoo , up in the north of town but a short walk from the Metro, forms part of the Smithsonian ensemble which at least means that admission is free. It sprawls down the steep slopes of the gorge cut by Rock Creek, with trails through lush vegetation and comparatively humane simulations of the home environments of more than three thousand creatures. Among the zoo's star attractions are the pandas Mei Xiang and Tian Tian, who arrived from the People's Republic of China in December 2000. The pair fills the absence left by the passing of Ling Ling and Hsing Hsing, the famous pair presented by Beijing during Richard Nixon's 1972 visit. The best time to catch the duo is first thing in the morning. In addition to the expected menagerie of giraffes and elephants, birds and bees, and lions and tigers, the zoo (or BioPark as it likes to call itself) boasts an unusual feature in its Think Tank , where orangutans assemble, commuting to and from their cages as they please by means of overhead cables across public areas of the zoo.