Arbroath Abbey in Angus

You're standing at Arbroath Abbey, right at the top of the High Street in the Scottish town of Arbroath. That red ruin in front of you was once the richest abbey in Scotland. Start with the west front, because most of it is still standing. There's the round-arched doorway that processions once passed through, flanked by what's left of two towers. Above it runs an open arcade, something you won't find anywhere else in medieval Scottish architecture. Higher still, you can make out the lower half of a great round window.