Of the 1,246 islands on Croatia"s fragmented coast, the unique isle of Bavljenac might be the most identifiable. It"s nicknamed "Fingerprint Island" for its miles of dry-stone walls that look like the whorled ridges of a human fingerprint. The tiny, uninhabited landmass in the Adriatic Sea was once an agricultural center. In the 19th century—the heyday of Croatian wine production— farmers from the nearest populated island built the winding walls on Bavljenac to protect olive trees and grapevines from the winds blowing in from the Adriatic.