Glendalough, also known as the city of the seven churches, was enclosed within a circular wall. The arch is built with roman style columns meaning the stones were cut specifically to scale and they held themselves up without the need for mortar. If even one of the stones were to be removed the entire structure would collapse. The very picturesque Gateway has the distinction of being Ireland’s only surviving example of a medieval gateway to an early monastic city. This structure was originally two-storied with two fine granite arches.