Though inner-city excavations are a dime a dozen in Italy, the Germans take what they can get: and the Roman palace (praetorium), sewer system, and Jewish synagogue-and-bath-complex that are slowly being unearthed in the center of the city are being treated with all the expected fanfare. It remains to this day still incomplete, but the site is open to visitors, who can tour the ruins, see many of the objects already excavated, and learn about the future museum that will eventually show the findings: including what will be Cologne's first Jewish Museum. Tours for adults are only available on a private basis.
Kleine Budengasse 2, Cologne, Germany