Igoumenitsa, Greece. This city on the Peloponnese offers a variety of ancient sites nearby. The Greek city of Cassopea dates from the 4th century BCE. Near the modern town of Preveza lie the ruins of Nikopolis, founded by the Roman Octavian to honor his defeat of Antony and Cleopatra’s naval fleet at the Battle of Actium in 31 BCE. Nearby are the ruins of an oracular site on the River Acheron, once believed to lead souls to the Underworld. Further afield, Meteora’s dramatic "monasteries in the sky," perched atop huge towers of rock overlooking the Plain of Thessaly, are one of Greece’s most impressive and unforgettable sites.