The Prehistoric Rock Art Sites in the Côa Valley and Siega Verde are a UNESCO transboundary World Heritage Site. It is located in the Côa Valley of Portugal and Siega Verde, Spain.

Côa Valley

The Prehistoric Rock-Art Site of the Côa Valley is an open-air Paleolithic archaeological site located in northeastern Portugal, near the border with Spain.

In the early 1990s, rock engravings were found in Vila Nova de Foz Côa during the building of a dam in the Côa River valley. These engravings include thousands of drawings of horses, cows, and other animals, as well as human and abstract shapes. The images are dated from 22,000 to 10,000 years B.C. Experts from UNESCO and other groups reviewed the sites. People in Portugal and around the world supported efforts to protect the art. In 1995, a new government was elected, and the dam project was canceled.

Since 1995, archaeologists have studied and recorded the prehistoric art in the area. The Archaeological Park of the Côa Valley (Parque Arqueológico do Vale do Côa) was created to welcome visitors and research the findings. The Côa Museum was built after a competition to design it.

The oldest drawings in the Côa Valley date from 22,000 to 20,000 years B.C. They show animals from nature. Between 20,000 and 18,000 years B.C., more horse drawings appeared. From 16,000 to 10,000 years B.C., the art became more detailed and showed Paleolithic styles. These images included horses with manes, aurochs with visible mouths and nostrils, and deer.

Other paintings from the Epipaleolithic period showed animals in a naturalistic style. Some designs from the Neolithic period were geometric or abstract. Others, mostly human figures, date from the Chalcolithic and Bronze Age.

Between the 5th and 1st centuries B.C., early societies created carvings of humans and animals, including weapons and symbols.

Rock art from the 17th to 20th centuries includes religious symbols, human and animal figures, and writings. These later works show boats, trains, bridges, planes, and scenes drawn by artists like António Seixas and Alcino Tomé.

In the 20th century, the Pocinho Dam and its reservoir likely covered many rock carvings. By the 1990s, explorers found important Paleolithic, Neolithic, and Chalcolithic carvings in the lower Côa Valley. These discoveries were made by Nelson Rabanda in 1991, though reports were published in 1994. Later, António Martinho Baptista identified Iron Age carvings as works by Celtic-Iberian tribes, such as the Medobrigenais or Zoilos. These cultures were first linked to the Côa findings.

In 1995, plans to build a dam were approved, and work began. However, an archaeologist, Nelson Rabanda, had already studied the area under the guidance of the national energy company (EDP) and the architectural heritage agency (IPPAR). He informed the press and UNESCO about the ancient art. EDP tried to prove the carvings were not old enough to stop the dam project, even though it would harm the site.

National controversy led IPPAR to ask UNESCO to review the site. In December 1994, Jean Clottes, an expert in prehistoric art, visited the area. UNESCO reports were not certain about canceling the dam, but Clottes noted that the Côa Valley is the largest open-air Paleolithic art site in Europe. He also said many carvings may have been lost under the Pocinho Dam. Nelson Rabanda confirmed this by studying submerged areas. Archaeologists found more carvings in places like Penascosa, Ribeira de Piscos, and others. A group called Movimento para a Salvação das Gravuras do Côa used the slogan "As gravuras não sabem nadar" ("The carvings don’t know how to swim") to protest the dam.

A second UNESCO team, led by Mounir Bouchenaki, confirmed many carvings were from the Paleolithic era. The Portuguese government’s push to continue the dam project caused political scandals and pressure from the international community. The dam was criticized in newspapers like The Sunday Times and The New York Times and by the BBC.

After UNESCO’s visit, IPPAR formed an international scientific group to study the art. This group included experts like António Beltrán and Jean Clottes. EDP promoted methods like making molds of carvings to save them, but continued supporting the dam. Some scientists used unproven methods to claim the carvings were not Paleolithic, which upset archaeologists and the public. A strong movement against the dam grew. In 1995, a new government was elected, and the dam project was canceled.

The government created systems to protect the site. The events led to the founding of the National Centre for Prehistoric Art (Centro Nacional de Arte Rupestre/CNART) and the Archaeological Park of the Côa Valley in 1997. The National Centre for Aquatic and Subaquatic Archaeology (Centro Nacional de Arqueologia Náutica e Subaquática/CNANS) opened in 1996.

In 1998, UNESCO declared the Prehistoric Rock-Art Sites of the Côa Valley a World Heritage Site.

In 2003, a study looked into reintroducing the Przewalski horse, a species shown in Paleolithic art.

By 2004, a competition was held to design the Côa Museum, won by architects Tiago Pimentel and Camilo Rebelo. Construction began in 2007.

More excavations in Fariseu from September to October 2005, led by Thierry Aubry, uncovered schist slabs (10 x 20 centimeters) with carvings.

Siega Verde

Siega Verde (Spanish pronunciation: [ˈsjeɣa ˈβeɾðe]; 40°41′51″N 6°39′40″W / 40.69750°N 6.66111°W / 40.69750; -6.66111) is an archaeological site located in Serranillo, Villar de la Yegua, in the province of Salamanca, Castile and León, Spain. It was added to the Côa Valley Paleolithic Art site on the World Heritage List in 2010.

The site includes a series of rock carvings discovered in 1988 by Professor Manuel Santoja Gómez during an archaeological survey of the Águeda River valley. Common subjects include horses, aurochs, deer, and goats. Other carvings depict bison, reindeer, and woolly rhinoceroses, which were still alive at the time.

The carvings are from the Gravettian culture of the Upper Paleolithic period, about 20,000 years ago. There are also more recent images of human figures from the Magdalenian period, around 9,000 years ago. The site has 91 panels spread across approximately 1 kilometer of rock.