In the past, the world's art museums won renown on the strength of their collections. Nowadays, however, the building housing the art can be just as much of an attraction itself. In fact, many modern museums should be studied from the outside before you step indoors to view the interior and its treasures, among them:

* Solomon R. Guggenheim Museum, New York City: Tiered like an upside-down layer cake, this controversial 1959 Frank Lloyd Wright building remains startling to behold. Inside, a spiral ramp leads visitors past the exhibits on a quarter-mile circular trek from the first floor to the top.

* Centre National d'Art et de Culture Georges Pompidou (Beaubourg), Paris: High-tech in design (the "guts" of the building are outside), this wonderfully colorful cultural center has quickly become one of the city's most popular attractions, with both Parisians and visitors.

* High Museum of Art, Atlanta: This much-applauded design by Richard Meier features a quite modern exterior of angles and curves, covered with white porcelain-enamel panels. Equally dramatic is the soaring interior gallery.

* East Building, National Gallery of Art, Washington, D.C.: I.M. Pei's grand addition to the National Gallery is clean and crisp on the outside and imposing -- and a lot of fun -- on the inside. Sightseers frequently scramble over the inviting balconies and bridges that climb to the ceiling before they finally settle down to see the exhibits.

* Kimbell Art Museum, Fort Worth: Serene, elegant and beautiful describe Louis I. Kahn's innovative and award-winning structure, considered one of the modernist architect's masterpieces.

* San Antonio Museum of Art, San Antonio: Not a new building, but an innovative adaptation of an old one. In 1981, the sprawling, castle-like structures of the old yellow-brick Lone Star brewery were transformed by twin glass elevators, skylights and a turret-to-turret glass skywalk into a dazzling showplace for modern art.