The castle in Enez, ancient Ainos, is located on a hill which is the highest point in the area, called the acropolis in the ancient times. In its heyday, the entire top of the hill was surrounded by high defensive walls. Access to the fortress was provided by two arched gates - located on the eastern and northern sides.

During the archaeological works carried out in the fortress, it was discovered that the rock on which the successive layers of civilization had accumulated is 7.5 meters below the present ground level. Chronologically, the oldest and deepest cultural strata date back to the 4th and 3rd millennium BCE. They prove that the oldest scientifically confirmed settlement in this area dates back to the Chalcolithic (Copper Age).

Another, higher cultural layer comes from the times of Greek colonization. The red-figure and black-figure ceramics unearthed in it are the evidence of close commercial and cultural contacts between Enez and mainland Greece, the islands in the Aegean Sea, and the cities in Western Anatolia. From this period, the traces of rooms and warehouses carved in the rock on a rectangular plan were also discovered. Thousands of sealed amphoras found in them were used to store and transport wine, oil, grains, and even fish.

The fortress, the remains of which can now be visited in Enez, dates back to the Byzantine times, most likely from the reign of Emperor Justinian I. The most famous Byzantine historian, Procopius of Caesarea, claims that the castle was erected to stop barbarians invading from the region of the Balkans.

In the fortress, to the left of the main gate, there are the remains of the vast Basilica of God's Wisdom (Hagia Sophia). Although less known and much less preserved than its famous namesake in Istanbul, the Basilica of Enez deserves attention as well. Built in the 6th century CE, in its heyday it was covered with an imposing dome that had collapsed long ago. However, a high, semicircular apse has been preserved, which is now protected against destruction by scaffolding. The narthex, i.e. vestibule of the basilica, decorated with a colonnade and arches, has also survived.

After the Ottomans conquered the territory of Thrace, the basilica was transformed into a mosque. The mihrab, located in the southern aisle, as well as painted wall decorations from that period can still be seen

A little further away from the main gate to the fortress, the remains of a small chapel were found during excavations. It was a chapel dedicated to Saint Gregory called the Miracle-Worker (Gregory Thaumaturgus) from Neocaesarea (now Nixar in the province of Tokat). The chapel was built in the 6th century and is decorated with rich floor mosaics.

Currently, long sections of the fortress walls have been preserved. It is worth to take a stroll through its extensive grounds to admire the views that extend from the embankments to the outer line of fortifications, the town of Enez, Saros Bay, and the mouth of the Meriç River. During the walk, you can take a closer look at the original brick walls, which have been heavily restored near the main gate.

It is also worth finding two lonely towers in the fortress. The first of them served for some time as a mint (tr. darphane), and the second, called the Bell Tower (tr. Çan Kulesi), was restored as a residential building.

In front of the entrance to the fortress, on the left, there is a courtyard where some finds have been exhibited, including the portrait of a Thracian rider carved in white marble. However, most of the exhibits discovered in Enez are on display in Edirne, in the local Archaeological Museum.