Cathedral by Peterodl
Built in the 12th century and once the largest cathedral in Scotland, the main tower of the cathedral collapsed and took much of the North wall along with it in the 1600's.By the early 1800's, much of the rubble was being used for various building projects around the town but by 1854, the town started to preserve the ruins for future generations.
The ruins are very impressive to walk through and there are diagrams and reference markers spread around the grounds.
You can walk through the cemetery next to the cathedral and see some very old grave stones.
Entrance to the grounds is free but there is a charge for the museum.