The acropolis of the city (Inner fortress, high city) is located on a 46-hectare plot of land in the area surrounded by fortifications. The western gate is a triumphal arch with three entrances. The gate, built with an architectural and plastic monument similar to the Propylon (monumental entrance) that provides the passage to the Augustus Sanctuary, was first uncovered during the excavations of the University of Michigan in the 1920s. Electromagnetic research on the city's plan in recent years has determined the location of many buildings under the ground and has shown that the regular, grid-shaped city plan of the Miletus architect Hippodamos, which was successfully applied in Hellenistic cities such as Priene and Miletos, was successfully applied in Antioch as well. The two known streets are the 90 + 320-meter Decumanus Maximanus starting from the West Gate and the 400-meter Cardo Maximus starting from the Nymphaeum (monumental fountain). The two streets intersect at a right angle about 70 meters south of the Tiberia Platea (Tiberius Field).
Temple of Augustus: The most monumental building complex of Antioch is reached after climbing the stairs of the Propylon. The temple, which is located on the highest point of the city on the plain obtained by carving the rocks with perseverance, was built with a richness that will astonish the visitor at first with its facade architecture. The construction of the temple in the sanctuary probably started when the emperor was alive and was dedicated to his name after his death. The visible structure is contemporary with the Propylon that provided its entrance, but there are also signs such as bullheads that the rock may have been built for another cult in earlier periods. The rock that was carved and leveled for the beliefs of the Mother Goddess Kybele and the Moon God Men, whose roots go back much further and whose dominance is known in the region, must have been transformed into an Emperor's temple under the rule of Rome.
St. Paul's Basilica: The first excavations in the basilica in the northwest of the city, one of the most important structures of Antioch, were started by Robinson and his team in the early 1920s. The building was last explored by the Yalvaç Museum. The structure, measuring 70x27 meters, extends in an east-west direction with the narthex (entrance) section of 27x13 meters in the west leaning against the city walls. Reflecting all the elements of the basilica plan, the building consists of three naves and a semicircular apse. The outer surface of the apse is surrounded by a hexagonal wall. The basilica was altered at a later stage, probably at the end of the 4th century. Its interior was completely filled at the first-floor level, the nave was covered with mosaics, and the entrances were given from the marble-paved courtyard built on the north side. The compressed floor at the top is dated to the same period as the entrance to the north courtyard. The angle difference between the axis of the building and the axis of the mosaics also shows the continuous change that the building has undergone. The mosaic, which was discovered and published in the first excavations, was later closed and is approximately 30 cm. underground today. It is learned from excavation reports and photographs that it was decorated with geometric and floral motifs in rectangular framed panels.
Theater: After the West Gate is passed, the beginning of the Decumanus Maximus Street towards the acropolis is seen. The street, which rises with a slight incline, reaches the theater after about 50 meters. It is very difficult to get an idea about the cavea (seat benches), diazoma (horizontal corridor dividing the cavea in the middle), radial stairs (kerkides), parados (side entrances), orchestra (the semi-circular area where the choir and musicians are located) and the stage building as it is today. Even when Arundell described the theater during his trip in 1833, he writes that most of the steps had been dismantled. During the excavations carried out in recent years, it has been understood that the width of the facade of the theater, whose cavea is wider than a semicircle, reached approximately 100 meters. In this case, we can compare the Antiocheia theater with the 15,000-seat Pamphylia Aspendos theater. The theater is bigger than the other important cities of Pisidia, Sagalassos (Ağlasun), Selge (Zerk) and Termessos (Güllük). It is possible to trace the original architecture of the theater back to the founding years of the colony and even to the Hellenistic Period, but it is imperative to wait for the excavations to continue for definitive interpretations.