Renzo Piano really is the go to guy for American art galleries. In addition to the Kimbell opposite Louis Kahn referred to in Peter's Out Yonder link, at Harvard he is doing the Fogg Extension next door to Corb's Carpenter Center and across the road from Jim Stirling's Sackler Museum. Not to mention John Andrew's Gund Hall on the opposite corner. There's a reason Jim called it the Harvard Architectural Zoo and they're expanding their collection.
Took some time off pursuing the post-industrial went out for the Carpenter Center 50th Birthday pilgrimage and there was Renzo's Fogg Extension next door.
Pretty much in the Fogg's view shadow as seen from the Harvard Yard but quite strong where it faces the Carpenter Center, Sackler Museum and Gund Hall.
Don't you just love lamp posts though, it reminded me of home.