Diyarbakır's single most conspicuous feature is its great circuit of basalt walls, probably dating from Roman times, although the present walls, around 6km in total length, date from early Byzantine times (AD 330–500). Be prudent when walking on and along the walls as there have been reports of attempted robberies. Try to go in a group and keep personal items and cameras safe.
There were originally four main gates: Harput Kapısı (north), Mardin Kapısı (south), Yenikapı (east) and Urfa Kapısı (west). Fortunately, the most easily accessible stretch of walls is also the most interesting in terms of inscriptions and decoration. Start near the Mardin Kapısı close to the Deliller Han, a stone caravanserai now home to the Otel Büyük Kervansaray. Don't miss Nur Burcu, the Yedi Kardeş Burcu, with two Seljuk lion bas-reliefs – only visible from outside the walls – and the bas-reliefs of the Malikşah Burcu. Ascend the walls of the İç Kale (keep) for fine views of the Tigris. The İç Kale has been undergoing restoration for several years, and includes the beautifully resurrected 3rd century AD St George Church. Other ongoing restoration projects include using an historic prison as a new location for the city's Archaeology Museum. At various spots inside the walls are brightly painted, open-air Sufi sarcophagi, notable for their turbans – their size is a symbol of spiritual authority. There's a cluster a few hundred metres northeast of the Urfa Kapısı.
