The largest art museum in the western hemisphere (spanning four blocks, it encompasses 2 million square feet), the Met is one of the city's supreme cultural institutions. Its permanent collection of nearly 3 million works of art from all over the world includes objects from the Paleolithic era to modern times -- an assemblage whose quality and range make this one of the world's greatest museums.

The Met first opened its doors on March 30, 1880, but the original Victorian Gothic redbrick building by Calvert Vaux has since been encased in other architecture, which in turn has been encased. The majestic 5th Avenue facade, designed by Richard Morris Hunt, was built in 1902 of gray Indiana limestone; later additions eventually surrounded the original building on the sides and back. (You can glimpse part of the museum's original redbrick facade in a room to the left of the top of the main staircase and on a side wall of the ground-floor European Sculpture Court.)

The 5th Avenue entrance leads into the Great Hall, a soaring neoclassical chamber that has been designated a landmark. Past the admission booths, a wide marble staircase leads up to the European paintings galleries, whose 2,500 works include Botticelli's The Last Communion of St. Jerome (circa 1490), Pieter Brueghel's The Harvesters (1565), El Greco's View of Toledo (circa 1590), Johannes Vermeer's Young Woman with a Water Jug (circa 1660), Velázquez's Juan de Pareja (1648), and Rembrandt's Aristotle with a Bust of Homer (1653). The arcaded European Sculpture Court includes Auguste Rodin's massive bronze The Burghers of Calais (1884-95).

The American Wing, in the northwest corner, is best approached from the first floor, where you enter through a refreshingly light and airy garden court graced with Tiffany stained-glass windows, cast-iron staircases by Louis Sullivan, and a marble federal-style facade taken from the Wall Street branch of the United States Bank. Take the elevator to the third floor and begin working your way down through the rooms decorated in period furniture -- everything from a Shaker retiring room to a federal-era ballroom to the living room of a Frank Lloyd Wright house -- and American paintings.

In the realm of 20th-century art, the Met was a latecomer, allowing the Museum of Modern Art and the Whitney to build their collections with little competition until the Metropolitan's contemporary art department was finally established in 1967. The Met has made up for lost time, however, and in 1987 it opened the three-story Lila Acheson Wallace Wing. Pablo Picasso's portrait of Gertrude Stein (1906) is the centerpiece of this collection. The Iris and B. Gerald Cantor Roof Garden, above this wing, open from May to late October, showcases 20th-century sculptures and provides a refreshing break with its unique view of Central Park and the Manhattan skyline.

Those with a taste for classical art should proceed to the left of the Great Hall on the first floor to see the Greek galleries. Grecian urns and mythological marble statuary are displayed beneath a skylighted, barrel-vaulted stone ceiling that forms one of the grandest museum spaces in the city. Although renovations are still in progress, Roman galleries are slated to open behind the Greek galleries, with a court for Roman sculpture, and space for the museum's collection of rare Roman wall paintings excavated from the lava of Mt. Vesuvius. The Met's awesome Egyptian collection, spanning some 4,000 years, is on the first floor, directly to the right of the Great Hall. Here you'll find papyrus pages from the Egyptian Book of the Dead, stone coffins engraved in hieroglyphics, and mummies. The collection's centerpiece is the Temple of Dendur, an entire Roman-period temple (circa 15 BC) donated by the Egyptian government in thanks for U.S. help in saving ancient monuments. Placed in a specially built gallery with views of Central Park, the temple faces east, as it did in its original location, and a pool of water has been installed at the same distance from it as the Nile once stood. Another spot suitable for contemplation is directly above the Egyptian treasures, in the Asian galleries: the Astor Court Chinese garden reproduces a Ming dynasty (1368-1644) scholar's courtyard, complete with water splashing over artfully positioned rocks.

Also on the first floor are the Medieval galleries. The Gothic sculptures, Byzantine enamels, and full-size baroque choir screen built in 1763 are impressive and may whet your appetite for the thousands of medieval objects displayed at the Cloisters, the Met's annex in Washington Heights. From the Medieval galleries continue straight on until you enter the cool, skylighted white space of the Lehman Wing, where the exquisite, mind-bogglingly large personal collection of the late donor, investment banker Robert Lehman, is displayed in rooms resembling those of his West 54th Street town house. The collection's strengths include old-master drawings; Renaissance paintings by Rembrandt, El Greco, Petrus Christus, and Hans Memling; French 18th-century furniture; and 19th-century canvases by Goya, Ingres, and Renoir. Even at peak periods, crowds tend to be sparse here. To the north of the Medieval Galleries is the Arms & Armor exhibit, which is full of chain mail, swords, shields, and fancy firearms. On the ground floor, the Costume Institute has changing exhibits of clothing and fashion spanning seven centuries that focus on subjects ranging from undergarments to Gianni Versace.

Although it exhibits roughly only a quarter of its vast holdings at any one time, the Met offers more than you can reasonably see in one visit. Focus on two to four sections and know that, somewhere, there's an empty exhibit that just might be more rewarding than the one you can't see due to the crowds. Walking tours and lectures are free with your admission contribution. Tours covering various sections of the museum begin about every 15 minutes on weekdays, less frequently on weekends; they depart from the tour board in the Great Hall. Self-guided audio tours can be rented at a desk in the Great Hall and often at the entrance to major exhibitions. Lectures, often related to temporary exhibitions, are given frequently. During evening hours on Friday and Saturday, cocktails are served accompanied by chamber music. COST: $12. Subway: 4, 5, 6 to 86th St.