Craigmillar Castle in Edinburgh

You're standing at Craigmillar Castle, a ruined medieval castle on a low hill about three miles south-east of Edinburgh's city centre. It's one of the best-preserved medieval castles in Scotland. Start with the high wall wrapped around it all. There's a round tower at every corner, with gun holes shaped like keyholes. They were meant for defence, but also simply for show. Over the gate in the north wall you'll see the arms of the Preston family, with the royal arms of Scotland above them.