The Gaziantep Fortress is worthy of attention due to its hidden history and its magnificence and is one of the best examples of fortresses in Turkey.
Its exact history is not known, but research has found that it was inhabited during the Calcoholitic Age. Its’ present form dates from the period of Justinian in the sixth Century AD. It is square in shape and has a circumference of 1200 metres.
The walls, which were built with large stones, were fortified by twelve towers. In addition, there is a mosque, a cistern and some ruins in the castle, and in the basement, caves, corridors, rooms and a water source may be seen.
At Belkis (Zeugma), 10 km south east of Nizip, ruins from the Greek, Roman and Byzantine Periods can be seen in the village of the same name.
Hromgia is 25 km from Yavuzeli and 62 km from Gaziantep. Although the precise history of Hromgia is unknown, it is thought to have been built during the late Hittite Period, around 840 B.C.
It is believed that in the Roman Period Chiristians made Hromgla a center of Christianity, and tried to spread Chiristianity to Hromgla and its surroundings. It is also said that John, one of Jesus' apostles, saved manuscripts of the Bible in in Hromgla which were later taken to Beriut. For this reason Hromgla is a sacred place for Christiants. When the crusaders were defeated and driven out of the region, the Moslems captured Hromgla and the surrounding area, and there are many remains in the castle and the area from the Turkish Islamic Period. In the castle, where characteristics of Turkish Islamic Ert can be found, there is also a mosque but it is not in use.
Tilmen Tumulus, 10km east of Islahiye, is 24m high and one of the biggest tumuli of the region. Excavations have affirmed there was a big city there in the late 3000s BC. The city consisted of inner and outer castles, the walls of which were fortified with large, cut stones.