Muness Castle in Shetland

You're standing at Muness Castle, on Unst, Scotland's most northerly inhabited island. That makes this the most northerly fortified house in the British Isles. Go any further north and you'll run out of castles. Take a look at the shape. It's a long rectangular block, roughly twenty-two by eight metres, with a chunky round tower on two opposite corners. Now look up at the other two corners. You can still see the projecting stones that once carried little turrets.