The stone carvings of Val Camonica (Camonica Valley) constitute the largest collections of prehistoric petroglyphs in the world. The collection was recognized by Unesco in 1979 and was Italy's first recognized World Heritage Site. Unesco has formally recognized more than 140,000 figures and symbols, but new discoveries have increased the number of catalogued incisions to between 200,000 and 300,000. The petroglyphs are spread on all surfaces of the valley, but concentrated in the areas of Darfo Boario Terme, Capo di Ponte, Nadro, Cimbergo and Paspardo.
Many of the incisions were made over a time period of 8000 years preceding the Iron Age (1st millennium BC), while petroglyphs of the last period are attributed to the people of Camunni, mentioned by Latin sources. The petroglyph tradition does not end abruptly. Engravings have been identified (although in very small number; not comparable with the great prehistoric activity) from the Roman period, medieval period and are possibly even contemporary, up to the 19th century. Most of the cuts have been made using the 'martellina' technique and lesser numbers obtained through graffiti.References:
The city walls of Avila were built in the 11th century to protect the citizens from the Moors. They have been well maintained throughout the centuries and are now a major tourist attraction as well as a UNESCO World Heritage Site. Visitors can walk around about half of the length of the walls.
The layout of the city is an even quadrilateral with a perimeter of 2,516 m. Its walls, which consist in part of stones already used in earlier constructions, have an average thickness of 3 m. Access to the city is afforded by nine gates of different periods; twin 20 m high towers, linked by a semi-circular arch, flank the oldest ones, Puerta de San Vicente and Puerta del Alcázar.