Castle Sinclair Girnigoe perches dramatically on the cliffs of Sinclair Bay, three miles north of Wick in Caithness, combining the ruins of two distinct phases of fortress building. The earlier Castle Girnigoe was constructed by William Sinclair, 2nd Earl of Caithness, between 1476 and 1496 as an early seat of Clan Sinclair. The early 17th-century expansion created what is now recognized as Castle Sinclair, though the original designation as separate castles reflects centuries of confusion over the structure's development. Designated a scheduled monument and the only Scottish castle listed by the World Monuments Fund, this sea-cliff fortress demands a steep walk over uneven ground to access its dramatic remains.