like Vinsanto. It is not easy to be a winegrower in Santorini; the hot and dry conditions give the soil a very low productivity. The yield per hectare is only 10 to 20% of the yields that are common in France or California. The island's wines are standardised and protected by the "Vinsanto" and "Santorini" OPAP designations of origin. Brewing A brewery, the Santorini Brewing Company, began operating out of Santorini in 2011, based in the island's wine region. Governance The present municipality of Thera (officially: "Thira", ), which covers all settlements on the islands of Santorini and Therasia, was formed at the 2011 local government reform, by the merger of the former Oia and Thera municipalities. Oia is now called a (community), within the municipality of Thera, and it consists of the local subdivisions () of Therasia and Oia. The municipality of Thera includes an additional 12 local subdivisions on Santorini island: Akrotiri, Emporio, Episkopis Gonia, Exo Gonia, Imerovigli, Karterados, Megalohori, Mesaria, Pyrgos Kallistis, Thera (the seat of the municipality), Vothon, and Vourvoulos. Towns and villages Akrotiri Ammoudi Athinios Emporio Finika Fira Firostefani Imerovigli Kamari Karterados Messaria Monolithos Oia Perissa Pyrgos Kallistis Vothonas Vourvoulos Attractions Architecture The traditional architecture of Santorini is similar to that of the other Cyclades, with low-lying cubical houses, made of local stone and whitewashed or limewashed with various volcanic ashes used as colours. These colours, in recent years, tend to replace white in the colour of house façades, according to the traditional architecture of the island as it was developed until the great earthquake of 1956. The unique characteristic is the common utilisation of the hypóskapha: extensions of houses dug sideways or downwards into the surrounding pumice. These rooms are prized because of the high insulation provided by the air-filled pumice, and are used as living quarters of unique coolness in the summer and warmth in the winter. These are premium storage space for produce, especially for wine cellaring: the Kánava wineries of Santorini. When strong earthquakes struck the island in 1956, half the buildings were completely destroyed and a large number suffered repairable damage. The underground dwellings along the ridge overlooking the caldera, where the instability of the soil was responsible for the great extent of the damage, needed to be evacuated. Most of the population of Santorini had to emigrate to Piraeus and Athens. Fortifications During the 15th and 16th centuries the