Ancient Thera was founded in the 9C BC on a magnificent site high above the Aegean Sea. It was a sizeable city in Antiquity with 5 000 inhabitants and 700 cisterns and reached the height of its importance under the Egyptian Ptolemies (300-150 BC), who established a naval base there. Thera declined under the Romans and was abandoned in the 13C. The ruins include the Temenos of Artemidoros; the agora; the Temple of Apollo; the terrace and the gymnasium of the Ephebes.

The cave of Andíparos on Andíparos Island lies about 160m deep into the slopes of Mount Ágios Ilías (400 steps). A vast chamber there, about 216m long by 203m wide and 18m high, is covered in a forest of stalactites resembling an underground cathedral. At Christmas in 1673, the French Ambassador to Constantinople had midnight mass celebrated there, attracting many people from the neighbouring islands. During the Romantic era the cave was visited by Byron and other artists.

From Skála harbour one can take a little boat trip (in a caique) over the waters of the caldera (volcanic bassin). The view of the towering cliffs of the crater is very impressive. The boat stops first at Néa Kaméni, where a tiring (due to the sun) but not difficult walk (25min) leads to the top of the volcano. There is a panoramic view of the outline of the original Round Island. Wisps of sulphureous smoke sometimes rise out of the last crater.

Ancient Thera was founded in the 9C BC on a magnificent site high above the Aegean Sea. It was a sizeable city in Antiquity with 5 000 inhabitants and 700 cisterns and reached the height of its importance under the Egyptian Ptolemies (300-150 BC), who established a naval base there. Thera declined under the Romans and was abandoned in the 13C. The ruins include the Temenos of Artemidoros; the agora; the Temple of Apollo; the terrace and the gymnasium of the Ephebes.