İznik's once-imposing Roman walls, renovated by the Byzantines, no longer dominate but parts of their 5km circumference remain impressive. Four main gates still transect the walls, while remains of 12 minor gates and 114 towers also stand.
The most impressive chunk of fortifications, still soaring between 10m and 13m in height, can be seen in the southeastern section between Lefke Gate and the southern Yenişehir Gate. Lefke Gate itself is interesting for its three Byzantine gateways.
İstanbul Gate, the ancient city's northern entrance, is the most impressive. Note the decorative features of carved stone heads facing outwards. Göl Gate has little left of its entranceway, nor does the minor Saray Gate, but it's photogenically situated over a quiet country lane set between olive groves and poplars. It's named this because Sultan Orhan (r 1326–61) had a palace (saray) nearby. İznik's ruined Roman Theatre is on the route between Atatürk Caddesi and the Saray Gate.