Where were the "trullo" stone buildings built?

A trullo is a traditional Apulian dry stone hut with a conical roof. Their style of construction is specific to the Itria Valley, in the Murge area of the Italian region of Apulia. Trulli generally were constructed as temporary field shelters and storehouses or, as permanent dwellings by small proprietors or agricultural labourers. In the town of Alberobello, in the province of Bari, whole districts contain dense concentrations of trulli.