“I need to produce great ideas,” said the printmaker Giovanni Battista Piranesi, “and I believe that if I were commissioned to design a new universe, I would be mad enough to undertake it.” Though Piranesi was an Italian architect, he became famous for his grand illusions in print. Born in Venice in 1720, trained as an engineer, Piranesi etched everything from fantastic building complexes to dreamlike surrealist structures. His background in stage design, coupled with tales of Ancient Rome told to him by his brother, a priest, inspired his visions. Piranesi’s floating bridges and palaces, his imposing dungeons, are here on view. —E.C.