Lying east of the lower lake, the ruins of the second monastery are the most important part of the complex. The 30m-high 10C round tower is the most striking feature; it was a watchtower and place of refuge. Beyond the entrance situated 4m above the ground, the walls get progressively thinner. In the roofless 10C cathedral, note the doorway and south bays. St Kevin’s church is a primitive stone roofed oratory and the site’s finest building.