Isabella Stewart Gardner Museum-Priceless!
The photo above shows part of the garden in the enclosed central courtyard. The glass-roofed enclosure was the first of its kind in America.
Here's a picture of the patron (by John Singer Sargent). It's on display at the museum.
Here's the Rembrandt they took and I remember it very well from seeing it before it was stolen. It was the kind of artwork you don't forget, and it's terrible that criminals have taken it from the public (and possibly harmed it).
Of course, the museum is still well worth a visit, with many, many treasures. Here's another view of the courtyard. (They don't allow photos to be taken anywhere else in the museum.)