This fascinating voyage calls on six countries known for their tumultuous, interrelated histories. The beautiful island of Santorini was formed by an ancient volcanic eruption, which supposedly destroyed the lost continent of Atlantis. The majestic architecture in Valletta reflects the fact that it was built for defense in the 16th century, and many of the fortifications are still intact. You might even trace the rise and fall of the Roman Empire in a sampling of Italian ports that includes Sicily’s marvelously medieval Taormina and the living museum of Rome. France’s outgoing Marseilles was founded by the Greeks in 600 B.C., conquered by the Romans, and proudly puts its history on display in a wealth of museums.