Sofia has been an area of continuous human habitation since at least the 30th millennium BC. The city has a history of nearly 7000 years, with the great attraction of the hot water springs that still flow abundantly in the centre of the city. The neolithic village in Slatina dating to the 5th–6th millennium BC is documented. Remains from another neolithic settlement around the National Art Gallery are traced to the 3rd–4th millennium BC, which has been the traditional centre of the city ever since.