Technopolis & Industrial Gas Museum

In the late 1990s, Athens revived this nineteenth-century industrial gasworks district and transformed it into a cultural center whose multiple buildings still buzz with energy. This is where the Athens Jazz Festival takes place each spring, but on permanent view are museums dedicated to intriguing things like industrial gas or, ahem, the Greek opera singer Maria Callas. There are innovation symposia, craft fairs, film screening, dance events, and a positively vibrant young nightlife scene each evening (after all, 700,000 people show up here each year).