large north gate of roman town fortifications at archaeological park, unesco site, xanten, north rhine-westphalia, germany

nordrheinwestfalen archaeologischer rhinewestphalia fortifications archaeological crenellations architecture archaeology constructed destination foundations niederrhein settlement westphalia flagstones inferioris frontiers fortified germaniae limestone nordrhein rhineland westfalen frontier heritage cultural germanic historic imposing original pavement germany arcades borders colonia emperor harbour history partial pattern regular replica tourism tourist traiana trajana western windows unesco xanten double arches access empire german border europe trajan travel