The historic peninsula of Aghia Eirini lies right across the cosmopoliatan Vourkari and was the site of one of the most important pre-historic settlements of the Aegean Sea. Its history begins in the Copper Era and ends in the Mycenaean years. It was one of the four ancient cities of Kea (Ioulida, Karthaia, Korissia) and an important trade center, surrounded by fortress (dating from the middle of the Copper Age, around 1700 BC).

In the area used to lie a Temple, many buildings - most of which were built during the post-Cycladic period (1600-1450 BC) - and an excellent network of stone-paved streets, an important cemetery in Kephalas cape. Visitrors can still see their remainings.

Among the most important discoveries found in the area are the clay statues of  the "Kores" (girls) wearing long clothes. Excavations have also revealed jars, clay ovens (known as "Sauce Boats), marble figurines and the narrow tall vessel with two handholds, known as "Depas Amphikypellon". All the discoveries found in Aghia Eirini area are exhibited in the Archaeological Museum of Kea in Ioulida. Nowdays the picturesque chapel of Aghia Eirini stands in the so named peninsula.

Further down lies the Koka (Coca) peninsula, an industrial area which once was an important station of coal refuelling, a main source of Kea's income in older days. One can still see the deserted coal warehouse, the worker's houses (built at the end of 19th century) and the central dock, used for ships's loadings.