Outside the East Wing of the National Art Gallery in Washington. Photo: Brendan Smialowski for The New York Times The National Gallery, founded in 1937 as a gift to the nation from the financier Andrew W. Mellon, opened its doors in 1941. It is the jewel...

A view of the Frick Collection’s Fragonard Room as seen from the Living Hall, which was briefly closed this month for its first serious refurbishing in nearly a century. Photos: Michael Falco for The New York Times Roberta Smith writes: "Time doesn’t...