Croatia is Border Land. The country lays on the geographic margin between central Europe and the Balkans, between the Adriatic and the Continent. Its very shape speaks of the divide. There is nothing compact, square or secure. Instead it curves around Bosnia and Herzegovina in a narrow arc, like a crescent moon or a boomerang. At no point is Croatia more than a few hundred miles wide; in most places it is much less. Our goal was to kayak its length, through the 1,246 islands lying like marbles atop what astronauts claim is the bluest sea on the planet, the Adriatic.