Trulli are traditional Apulian houses, they are an extraordinary example of construction in dry stone with a conical or pyramid-shaped roof (the name derives from the Greek τρούλος, or “dome”), a technique which dates back to the pre-historic era and is still in use today in the region of Apulia. They are common in the entire Itria Valley as rural shelters for livestock or agricultural equipment, but in Alberobello it is possible to see entire concentrations: in the historical centre alone there are more than 1,500, almost all in perfect condition. The trulli of Alberobello were listed as UNESCO world heritage in 1996 in the World Heritage List as significant examples of spontaneous architecture inserted in an urban and landscape context of great historical value.
According to several studies, the trulli were first constructed in the Fourteenth century as a stratagem to avoid paying taxes! The King of Naples had, in fact, imposed a tariff for each new village erected. The Count of Acquaviva, feudal lord of the area, made an agreement with the colonists so that mortar would not be used to join the blocks with which their homes were built, so that in this way they maintained the aspect of precarious constructions, easy to demolish and therefore, non-taxable. Whatever their origin, the trulli are anything but precarious: their structure, even if without sustaining and binding elements, has, in fact, an extraordinary stability and demonstrates the use of particularly clever techniques.
The construction of the trulli is entrusted to master trulli builders, or trullari, who have passed this art down from generation to generation for centuries. The plan is roughly circular. The walls are built with an internal wall and an exterior one made of heavy blocks of limestone. Between these two walls there is a space filled with topsoil and stone rubble. This solution, together with the thickness of the walls and the scarce presence of windows, ensures that the interior environment provides excellent temperature regulation. The roofs are also made of a double layer: an interior covering of limestone slabs called ‘chianche’, set in a concentric pattern, using larger to smaller slabs as they are being set, culminating in a keystone; and an outer waterproof dome built of smaller slabs called ‘chiancarelle’. The cornice protruding from the roof is ingenious, it used to collect rain water and drain it into specific cisterns.
At the top of the domes, bright white decorative pinnacles stand out, their function is to keep bad spirits and negative forces far away. On the roofs, religious symbols or symbols tied to popular tradition are often drawn in white ash. The trulli are not only a legacy from the past: visiting the lovely town of Alberobello means coming into contact with an ancient tradition which still today characterises an entire community.