The second longest cathedral in Ireland 

This was the location of a 6th-century monastery founded by St Canice Cathedral was built between 1202 and 1285 and is the second-longest and one of the best-preserved in Ireland. Inside you can see effigy tombs, The Great East Window, and The Kytler Grave Slab. Its floor is paved with four different types of marble representing the 4 provinces of Ireland. The round tower is the oldest standing structure in Kilkenny City and is one of only two that the public can climb in Ireland (the other is in Kildare Town).

Thanks to Photasma for great video