Lindisfarne Castle built
1550 CE.
Shown on the map at 55.669°, -1.785°.
Lindisfarne Castle is a 16th-century castle located on Holy Island, near Berwick-upon-Tweed, Northumberland, England, much altered by Sir Edwin Lutyens in 1901. The island is accessible from the mainland at low tide by means of a causeway.
Text from the Wikipedia article Lindisfarne Castle, licensed CC BY-SA 4.0.