Acropolis of ancient Eresos (Vigla Hill) is where a section of the pre-hellenistic polygonal wall lies and on the hilltop there are ruins of Genoese and Turkish turrets and ruins of a medieval castle and a small cistern dating from the Roman Times.

The Church of Agios (Saint) Andreas.
The ruins of a Paleochristian church lie in the area directly behind the contemporary beautiful church of Saint Andrea of Skala Eresos.
According to archaeological findings this paleochristian church was a three-aisled Basilica dating from the first half of the 5^th century.

The mosaic floor decor of the central aisle is a superb work of art. The geometric figures, representations from the plant and animal world inspire awe and admiration.

On the same premises stands a building which houses a sarcophagus with the relics of Saint Andreas, the patron saint of Eresos (+740a.C).

Paleochristian basilica of Afentelli
Approximately two kilometres away, to the west of the estuary of river Chalandra at the “Afentelli” site, lie the ruins of the second Christian monument, a temple of the same style as that of St Andreas. It is three-aisled church which was built during the mid - 5^th century. It is believed that this is where the School of the doctor, philosopher and botanist Theophrastus existed. The mosaics that were found on the site include remarkable representations of peacocks which are in very good condition. The bases of the pillars and the capitals are of the Ionian style, while the famous “egkainio”, an item of particular interest is kept at the archaeological museum. The “egkainio” is a small marble sarcophagus which contained the relics and unction of the Saint.

The Museum of Eresos
The Museum of Eresos is located behind the church of Agios Andreas. The collection contains dark and red-figured lekythuses dating from the 5^th and 6^th century, chrismals from 6th century b.C., ancient coins, relief tombstones, corbels of the basilicas of St Andrea and Afentelli, inscriptions in the Aeolian vernacular refering to the decrees of the polis etc. The museum collection also includes the anchor of the turkish frigate "Moving Mountain", which D. Papanikolis set fire to in the bay of Eresos, on 27^th May in 1821.

The Monastery of Pithari (Moni Pithariou)

Founded during the 17^th century, this monastery is consecrated to the archangels. This beautiful monastery, built in a ravine of oaks and planes, is at 30 minutes’ distance from Eresos.

Moni Ipsilou (Monastery of Ipsilos)
The Monastery of Ipsilou is 12km from Eresos. This imposing building stands on the highest peak of the Ordymnos range, 551m above sea level. Its door is shut from sunset until sunrise.
The monastery was founded before 800 a.C. by Saint Theophanis of Sygriani and is the most ancient monastery of Lesbos (built in 1101). The patriarchal bill of 1331 proves that it is a byzantine monastery. In 1462 the monastery was ransacked by the Turks. The monastery was raided in 1821 and 1851 by the Turks who seized the greatest part of its valuable heirloom. In 1967 it was devastated by fire and most of the western and eastern wing and church were destroyed. Its restoration work was financed by the Archaeological Service with the attention of the Metropolite of Mytilene, in 1971.
The catholic of the monastery is dedicated to Saint John the Theologian who is commemorated on the 8^th May.
There are six large icons of the byzantine style on the temple, which portray the image of Christ, Virgin Mary and Saint John the Theologian. The monastery keeps stoles embroidered in gold, Gospel wrappers, magnificent altar clothes from 1588, 1622, 1730 και 1825 decorated with religious representations, six shrines containing the relics of Saints, gold plated Gospels and a multitude of sacred vessels belonging to different periods, crosses inlaid with rubies and pearls, gold plated vessels with artistic representations etc. The collection also contains a large number of documents, manuscripts and codes that are of special interest to researchers studying history and ecclesiastical life.

The Petrified Forest
Petrified plant fossils can be found in the territory on the West side of Lesbos island, in the Municipality of Eresos and the Communes of Antissa and Sygri, over an area of roughly 1.500 hectares. This area, the Petrified forest, is know both in Greece and world-wide.

In recognision of the rare paleontoligical and geomorphological value of this unique natural creation, the state put a special decree on the area, Presidential Decree 443/1985 (Official Journal of the Hellenic Republic 160 issue Α'/19-9-85) in order to define the legal status of the Petrified Forest and safeguard its preservation and rational management.

According to the above mentioned decree, five areas, both land and sea areas, are declared “Protected Monuments of Nature”. This area of 1.500 hectares contains both groups of fossils as well as individual petrified trunks