The churches of Santorini, although very much part of the cubist architectural style, show a Western influence in their relatively large size. The volcano's eruptions and the catastrophic earthquakes that shattered the island from time to time strengthened the religious fervour of the locals, which intensified when they were confronted with Catholicism during the Frankish occupation.

Thus before the 1956 earthquake, the island boasted some 260 churches. Most of those that have survived are of the one-aisled basilica type with dome, while others are cruciform in shape with dome.

The dome, which may be white, as in most churches, or blue, is frequently ridged rather than smooth. Sometimes it is capped by a lantern, a clearly Renaissance touch. The facade of the churches and cathedrals alike is dominated by the presence of twin bell towers. Santorini's monasteries are massive, often reminiscent of fortresses, such as the monastery of Profitis Ilias. They have an inner courtyard, arcades and impressive bell towers.