Midtown's only major green space has become one of the best-loved and most beautiful small parks in the city. Named for the poet and editor William Cullen Bryant (1794-1878), the 8-acre park was originally known as Reservoir Square (the adjacent main branch of the New York Public Library stands on the former site of the city reservoir). America's first World's Fair, the Crystal Palace Exhibition, was held here in 1853-54. Today London plane trees and formal flower beds line the perimeter of its central lawn. In temperate months the park draws thousands of lunching office workers; in summer it hosts live jazz and comedy concerts and sponsors free outdoor film screenings on Monday at dusk. At the east side of the park, near a squatting bronze cast of Gertrude Stein, is the open-air Bryant Park Café, which is open April 15-October 15, and the stylish Bryant Park Grill, which has a rooftop garden. The New York Chess Society sets up public tables near the west-end fountain in good weather (a sign set in the lawn reads sociable games arranged). In February and early September giant white tents spring up here for the New York fashion shows. Oct.-Apr., daily 7-7; May-Sept., weekdays 7 AM-8 PM, weekends 7 AM-11 PM. Subway: B, D, F, V to 42nd St.; 7 to 5th Ave.