IN a remote archipelago in the North Atlantic, there’s a long, slender island that locals say is shaped like a wooden flute. Unlike its larger neighbors, this island is not accessible via bridge or tunnel, only by ferry from Borðoy, a 20-minute passage that brings you to the hamlet of Syðradalur. From there, you drive north along the island’s only road, passing through four dank and somewhat spooky mountain tunnels — the flute’s finger holes — until you reach Trøllanes, population 20. Here, you park your car and hike to your goal, Kallur Lighthouse, a squat beacon set high above the churning ocean on the island’s northernmost tip.
Providing the trail hasn’t been closed because the wind is too strong or the fog too thick, the hour-long hike to the…