From the website:
"The Smithsonian Institution has two museums of Asian art: the Freer Gallery of Art, which opened to the public in 1923, and the Arthur M. Sackler Gallery, which welcomed its first visitors in 1987. Both are physically connected by an underground passageway and ideologically linked through the study, exhibition, and sheer love of Asian art. In addition, the Freer Gallery contains an important collection of nineteenth century American art punctuated by James McNeill Whistler's Peacock Room, perhaps one of the earliest (and certainly one of the most controversial) art installations on record.
Each building has its own aesthetic. The Freer is designed in a classical style whose architectural nexus is a courtyard that used to house live peacocks in the museum's early days. It was Charles Lang Freer's goal to facilitate the appreciation of world cultures through art, a noble undertaking as important today as it was more than a century ago, when he first willed his artwork and archives to the nation.
The Sackler takes you on an underground journey and is home to Dr. Arthur Sackler's incomparable collection of art, including some of the most important ancient Chinese jades and bronzes in the world. In addition, the Sackler Gallery contains works that have been acquired in the last twenty years and also features the Perspectives series of contemporary art that greets and often surprises visitors when they first enter the Gallery."
http://www.asia.si.edu/