Ancient Thassos, Horigico Monument and the temple of Apollo Pithio are some of the most important archaeological monuments of the ancient city of Thassos. Thassos was built around 700 B.C. by Parianous. Their chief was Telesiklis, the father of Archiligou. The installation of the Greeks is related to the exploitation of the mines of Pageos. Thassos became very quickly a commercial and spiritual center. The discoveries prove that the ancient city of Thassos was developed due to its localization, its port and the mines of Pageos.

The ruins of Agora, that was the politician and religious center, show the way of life of those times. It worth visiting Propilea, the tomb of Glaukos (7th century), the north-eastern gallery (4th century) and the south-western gallery with the seven entries.

Acropolis is probably medieval, but some of the ancient ruins are dating back to the 5th century.

The temple of Pithio Apollo has archaic style. It has three different parts. It was built around 500 b.C.

The base of the Horigico Monument is maintained til our days in a very good condition. It is located in the yard of the temple of Dionysus. There is one sign dedicated in Virtuus Demon. The ceremony of the adoration dates back to 4th century.

The gate of the goddess with the chariot is located near the ship yards. The walls of the gate are dated back to the 5th century. On the walls there is one bas-relief that represents the goddess sitting in the chariot, which has two horses, with Ermis holding the reins.

The gate of Silinos has on the west side one bas-relief that represents Silinos. Silinos is the patron of the city. The bas-relief is known from the archaic coins of Thasos.

The gate of Hercules and Dionysus is located next to the west side of the gate of Silinos. Its width is 4,60m and its height is more than 7 meters. There were two bas-relieves. One with Hercules and one with Dionysus. The first one is now located in the museum of Istanbul, while the second one has been lost. The gate is dated back to the 6th or 5th century.

The arch Karakala is located near to the gate of Hercules. The memorial site refers the names of Karakallas, Ioulia Domna, Septimios Seviros (213-217 D.C). There was a statue of Karakalla.

The holy of Poseidon is located near to the Horigico Monument, near the sea. In the façade located on the right side of the entrance there is the altar of Ira. In the museum there is one memorial sign that describes the ceremony of the adoration.