Skaros Rock

This guide to Skaros Rock in Santorini opens with a number worth pausing on: zero, the successful sieges ever mounted against a rock crammed with two hundred houses, a cathedral and monasteries. It goes back to 1207, when Venetian builders raised the first fortress here under Marco Sanudo, making this ridge the fortified capital of the whole island for centuries. Pirates, Ottoman fleets and Venetian rivals all failed to take it by force, so the guide turns to a different kind of threat entirely. Walk the narrow spine to where a drawbridge once let residents cut themselves off from the mainland below.