In southeast Europe agrarian societies first appeared in the 7th millennium BC, attested by one of the earliest farming sites of Europe, discovered in Vashtëmi, southeastern Albania and dating back to 6,500 BC. Anthropomorphic figurines have been found in the Balkans from 6000 BC, and in Central Europe by c. 5800 BC (La Hoguette). Among the earliest cultural complexes of this area are the Sesklo culture in Thessaly, which later expanded in the Balkans giving rise to Starčevo-Körös (Cris), Linearbandkeramik, and Vinča. Through a combination of cultural diffusion and migration of peoples, the Neolithic traditions spread west and northwards to reach northwestern Europe by around 4500 BC. The Vinča culture may have created the earliest system of writing, the Vinča signs, though archaeologist Shan Winn believes they most likely represented pictograms and ideograms rather than a truly developed form of writing. The Cucuteni-Trypillian culture built enormous settlements in Romania, Moldova and Ukraine from 5300 to 2300 BC. The megalithic temple complexes of Ġgantija on the Mediterranean island of Gozo (in the Maltese archipelago) and of Mnajdra (Malta) are notable for their gigantic Neolithic structures, the oldest of which date back to c. 3600 BC. The Hypogeum of Ħal-Saflieni, Paola, Malta, is a subterranean structure excavated c. 2500 BC; originally a sanctuary, it became a necropolis, the only prehistoric underground temple in the world, and showing a degree of artistry in stone sculpture unique in prehistory to the Maltese islands. After 2500 BC, the Maltese Islands were depopulated for several decades until the arrival of a new influx of Bronze Age immigrants, a culture that cremated its dead and introduced smaller megalithic structures called dolmens to Malta. In most cases there are small chambers here, with the cover made of a large slab placed on upright stones. They are claimed to belong to a population certainly different from that which built the previous megalithic temples. It is presumed the population arrived from Sicily because of the similarity of Maltese dolmens to some small constructions found in the largest island of the Mediterranean sea.