Siega Verde petroglyph. Prehistoric rock carvings (petroglyph) of an auroch, wolf (or dog), and horse. The auroch (wild cattle) is the main figure, with the head and horns at left. Within the body of the auroch is the smaller figure of a dog or wolf. At upper centre is the head and shoulders of a horse. This carving is part of the collection of petroglyphs at the Siega Verde site, in the province of Salamanca, Spain. The carvings date to the Upper Palaeolithic (around 20,000 years ago) and are thought to have been produced by the Gravettian culture. Discovered in 1988, it was made part of a UNESCO World Heritage Site in 2010.