57.3900°N, 18.1800°E.
Folhammar Trojaborg is a prehistoric or medieval stone-formation labyrinth in Gotland Island, Sweden. The design is a classical baltic layout with 8 circuits, 9 walls, approximately 25 metres in diameter, built of stone. Construction date is recorded as unknown in the surveyed catalogue. Current condition: intact. A rare 9-wall spiral-center Baltic-type labyrinth at Folhammar, unusually oval at 25x15 meters — making it one of the largest stone labyrinths on Gotland. Documentation sources: Gotland Trojaborgs PDF. Listed in the surveyed catalogue as one node in a larger global registry of the same single design. 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.