Few travelers to Croatia leave without visiting Dubrovnik, a medieval walled city of white stone and red roofs, jutting picturesquely into the Adriatic. Because of its well-preserved beauty, Dubrovnik’s main industry is now tourism, but the city was once the capital of the Republic of Ragusa. Wealthy Ragusa managed to retain its independence, despite its precarious position between Venice and the Ottoman Empire, only losing it, like Venice, when Napoleon invaded. And, like Venice, Dubrovnik currently suffers from invaders of a different sort: large cruise ships. In the summer high season, they make the walled center insufferable. More than one local related how, when multiple ships docked on the same day last year, such was the crush of tourists that the Stradun, Dubrovnik’s pedestrian-only main street, became impassable. Visiting Dubrovnik — smaller than Venice and less capable of handling crowds — requires some strategy.