Come spring, the gardens at Dumbarton Oaks in Georgetown are filled with strollers soaking up the sight of wisteria in bloom and other wonders. But winter can be beautiful too, in a very different way, as the skeletal structure of the trees and Beatrix Farrand's extraordinary 10-acre landscape design assert themselves. Winter visits have an added advantage: Though a fee is charged in the spring and summer months, the gardens are open free every day November through March, from 2 to 5 (except national holidays).

If it gets too cold, there's another wonder next door: the newly renovated Dumbarton Oaks museum, with its treasure trove of ancient sculpture, objects, jewels and textiles from Byzantine, Coptic and pre-Columbian times. Some of the finest examples in the world have been reinstalled in the welcoming skylit Courtyard Gallery, completed just last year by the Washington architectural firm of Hartman-Cox, and in the adjoining space given over to Dumbarton's unique collection of Byzantine ivories, bronzes, mosaics and decorative arts dating from 330 to 1453. They connect with the dazzling pre-Columbian galleries, completed in 1963 by Philip Johnson.

There's also a garden library and rare book room at Dumbarton Oaks, but they are primarily devoted to scholarly research in botanical subjects and landscape design and open to the public only on weekends, when and if guards are available. In the library, along with manuscripts, can be seen some paintings by Edgar Degas, Odilon Redon and others. Even when the rare book room is closed, two cases of materials from its collections are always on view in a nearby hallway, celebrating the 50th anniversary of the gardens given to Harvard University by Robert and Mildred Woods Bliss in 1940. The buildings and gardens are maintained by endowments from the Bliss family.