From power station to public building, London’s Tate Modern has rewritten the rules for what an art museum can be.

There’s no sign outside of Philadelphia’s newest and smallest art museum. You find it by walking west on Locust Street from Broad. Go past the four antique gas lamps and duck into the back entrance.

Heneghan Peng, WXY, Reed Hilderbrand, and Gustafson Porter + Bowman collaborated on the $53 million project at the open-air museum in New York's Hudson Valley.