The city of Antakya is home to several ancient monuments dating back to the Seleucid and Roman empires. These include the city walls, the Iron Gate (a gate and dam structure which was part of the city walls), the Roman Podium Temple and the Trajan aqueduct. Despite their historic importance, these structures have received little scientific attention to date. This study describes a brief history of these structures, and shares observations on their current state, with a particular emphasis on the damage they have sustained during the 2023 Kahramanmaras earthquakes and the environmental degradation mechanisms affecting the structures. Then, data collection activities to improve our current understanding of the materials and construction techniques of these structures, are introduced. Preliminary results are presented on the comparative non-destructive evaluation of building materials, using Schmidt hammer and Ultrasonic Pulse Velocity measurements. The results indicate the use of stones with variable mechanical properties, alongside high-quality mortars.