The largest rock carving found in northern Greece (2.5 x 1.9 meters) is on the banks of Lake Heimaditida, but the most impressive are those in Serres and Kavala. Those found most recently are in the Angiti Gorge in Serres, where there are about 60 carvings at the entrance to the cave, which Hatzilazaridis says were done at different times, thousands of years apart. All are a reddish clay or iron-oxide color. Some are perfectly proportioned, indicating that the artist was a specialist at this difficult task. There are pictures of male and female deer, bows and arrows, horsemen with and without armor, a person leading a bear, someone else leading a laden beast, a deer with an arrow or lance in its belly and many other drawings which are abstract or difficult to understand. Other pictures show horsemen ready to fight, and someone holding a lance or banner. At Palaio Hortokopi is a picture of some kind of cattle attached to a plow. At Folia, near the top of Mt Simvolo, are more than 200 scenes carved by by succeeding generations. They include the depiction of boats (the smallest of which has four stone anchors), axes, humans, animals, plants, trees, crosses, circles, semicircles, labyrinths and other lines. Hidden treasure The worst enemies of rock paintings are contemporary treasure hunters. Unlike other rural inhabitants who recognize that these are ancient artifacts in and of themselves, treasure seekers think the marks point to the location of hidden treasure, and they destroy them, either while searching or in the attempt to prevent others from searching the same area. Rock paintings of the world Rock paintings are found wherever there has been human habitation. The best known are those in southwestern France, northern Spain, Italy, Scandinavia, the Sahara, Tanzania, Bulgaria, Siberia and Australia. In Greece, where rock paintings have been studied since 1950, they have been found in Naxos (the largest collection is at Apeiranthos), Pangaios, Roussa, Goniko in Evros, Petrota Maroneias in Rhodope, Crete (at Asfentou), the Mani, Evia, Milos, Kero, Yioura, the mountains of Lekani and Simvolo in Kavala (in the villages of Kryoneri, Zygos and Philippi), Simvoli and Alistrati in Serres (especially beside the Angiti River), the highlands of Drama, Loutra Aridaias in Pella, around Lake Heimaditida in Florina, Halkidiki and at Mount Athos. The paintings in Greece were created using different methods, being scratched or carved with hard, fine, sharp objects. It is not certain what tools were used, but tools made from obsidian and quartz have been found in the past. «Rock carvings comprise a significant chapter in the history of humanity, which can illuminate the unknown past,» remarks Hatzilazaridis.