An Early Christian site founded by St. Ciarán in the mid-6th century on the eastern bank of the River Shannon. The site includes the ruins of a cathedral, seven churches (10th -13th century), two round towers, three high crosses and the largest collection of Early Christian grave slabs in Western Europe. The original high crosses and a selection of grave slabs are on display in the visitor centre. As this site is managed by the OPW, school tour visits are permitted free of charge provided certain conditions are met.