On my recent trip to York, I came across the ruins of St. Mary's. My lack of adequate prep for the trip saw to it that I knew nothing of the structure's existance! So imagine my surprise when I came across the walls of the nave.
While I was able to see a good amount of the abbey, there were some structures deeper in the park that I missed. Guess it just means I must return to York on another day.
The full report on the abbey can be found under the UK Tours section to the right of this page.