3 Days in Athens, Greece

"Alternatively, dedicate your final day to the Stavros Niarchos Foundation Cultural Center near the Bay of Faliro, where you can do pilates on the Versailles-inspired Great Lawn of Stavros Niarchos Park, watch a ballet in the 1,400-seat main hall, catch the Greek National Opera, or even hole up in the brand new National Library of Greece—all within a sleek, Renzo Piano–designed modernist building. (Just this month, the Chamber Music Society of Lincoln Center became the first U.S. group to perform there.) Bonus: Visitors can rent bikes to ride around the cultural center’s massive park between 9 a.m. and 9 p.m."