Svan towers (Georgian: სვანური კოშკი, translit.: svanuri k'oshk'i) refers to the tower houses built as defensive dwellings, common in the Georgian historical region of Svaneti and today incorporated in Samegrelo-Zemo Svaneti. The oldest are dated 8th or 9th century, the newest was built in the 18th century. A Svan tower is on average 20 to 25 meters high and has four or five, more rarely six floors. The ground floor, whose walls are up to 1.5 meters wide, usually has no doors and no windows. The entrance is usually at the level of an upper floor. The upper part of the tower is narrower than the lower one, and the width of the walls also decreases to 0.7-0.8 meters. The floors are connected by a wooden ladder. The upper part of the tower ends in a so-called crown with roof. On each side the tower has holes. The Svan towers are either rebuilt into residential buildings or are vacant.