Alberobello, in Apulia, with its Trulli is one of the 51 Italian sites recognized by UNESCO. The name, of greek origin, indicates the ancient stone conical buildings, of prehistoric origin. The stone used for the buildings was obtained from the limestone plateau of the Murgia. Today Alberobello is one of the best preserved urban areas in Europe which presents many prehistoric building techniques. The origin of the Trulli dating back to the mid-14th century, the period when the territory was granted to the first Count of Conversano, in recognition of his service during the Crusades. The plant of the trulli is circular; based on natural rock it joins the heavy masonry in lime. Generally are modular buildings: the interiors are distributed around the central compartment. The thickness of the walls and the scarcity of windows ensure an optimal thermal equilibrium: warmth in winter and cool in summer. The roof is composed of a dome of limestone slabs positioned into smaller and smaller concentric series, the so-called “chianche” (inside) and the thinner “chiancarelle” (outside). Important the ceiling, often decorated with esoteric reasons or spiritual or of mercy. Ingenious the presence of a ledge protruding from the roof used to collect rainwater in special tanks. The Trulli are a unique example of ancient construction that survives and are still used today.