Travel from the Bosphorus to the Caucasus, around the Crimea to shores where the Danube spills out into the Black Sea. You’ll wander promenades lined with curious Trees of Friendship, visit spas that have pepped up visitors for generations, and sample vines that produce surprisingly fine wines. Trace Potemkin Steps in Odessa, Romanian streets where Ovid is said to have lived and discover Bulgaria’s beautiful peninsula where ancient Nesebur has perched for 3,000 years and more.