The Grote Kerk of Dordrecht (Dordrecht Minster) is a large medieval basilica with transept, build in Brabantine Gothic style and the northernmost representative of this style, which is found a lot in Flanders (Belgium).
St.Patrick's Cathedral in Dublin is the largest of the city's two cathedral (the other one being Christchurch Cathedral). Unusually, the cathedral is not the seat of a bishop, but the National Cathedral of Ireland, this situation has existed since the 13th century. The dean of the cathedral is the ordinary of the church, the most famous holder of this office was the author Jonathan Swift (of Gulliver's Travels)
This isolated chapel was attached to a monastery in the village below the hill. It dates to about 1400 and probably survived the dissolution of the monasteries because it is on a hill which overlooks the sea and the chapel may have been used as a lighthouse.
I could not find out anything about the terracing on the hill, so I don't know whether it is prehistoric or the result of medieval farming. There are a lot of prehistoric earthworks in the area and if these terraces are prehistoric, I don't know why this place isn't as famous as Glastonbury Tor.
Glendalough is a glacial valley in County Wicklow, Ireland and famous for it's early Medieval ruins of a monastic settlement. The monastry was founded in the 6th century by St. Kevin, a hermit priest. The site was attacked and destroyed by English forces in the late 14th century.
Christ Church Cathedral is the oldest of the two mediaval cathedrals in Dublin. It is both the site of the Church of Ireland (Anglican) archbishop as well as the Roman Catholic archbishop of Dublin. In practical use it is a Church of Ireland cathedral only.