The Renwick Gallery is housed in a grand Second Empire building.  
Renwick, in a surprising twist, is the name of the architect, not the 
name of an art collector or donor.  (By the way, Renwick also designed 
the Smithsonian Castle.  He's a talented guy.)  The building was built 
for the Corcoran Gallery, which is now in a different building a block 
away.  (The Corcoran moved when it ran out of space.  The building was 
sold to the government and went through a number of incarnations for 
various agencies before being transferred to the Smithsonian.)