Talk about history. This cathedral was built starting back in the 10th century. It took so long back in those days that it wasn't even finished (to our knowledge) until the 13th century. The cathedral is much smaller in person than it looked in pictures, but what it lacked in size, it made up for in history and beauty. Many of the buildings around this area had been destroyed by Vikings in the 1200s, but what remains of this cathedral has been preserved remarkably well. Glendalough, despite being small, has 7 churches, and this is the largest of the churches.