57.9250°N, 18.6840°E.
Hallshuk Lighthouse Trojaborg is a prehistoric or medieval stone-formation labyrinth in Gotland Island, Sweden. The design is a classical 15circuit layout with 15 circuits, 16 walls, approximately 16 metres in diameter, built of stone. Construction date is recorded as unknown in the surveyed catalogue. Current condition: intact. A 16-wall triple-angle classical labyrinth near Hallshuk Lighthouse on Gotland's northwest coast — where dramatic sea stacks (raukar) and fossil-rich Silurian limestone create an otherworldly landscape. Documentation sources: Gotland Trojaborgs PDF. The same seven-circuit topology appears at this site as at every other classical labyrinth on Earth. The labyrinth is one of several hundred sites of this type catalogued globally; each preserves the same unicursal walking-pattern with regional variation in scale, material, and date.
The labyrinth tradition spans at least 4,000 years of documented practice across northern Europe, the Mediterranean, the British Isles, North America, and the Indian subcontinent.