The United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage Sites are places of importance to cultural or natural heritage as described in the UNESCO World Heritage Convention, established in 1972. Spain accepted the convention on May 4, 1982, making its historical sites eligible for inclusion on the list.
Sites in Spain were first inscribed on the list at the 8th Session of the World Heritage Committee, held in Buenos Aires, Argentina in 1984. At that session, five sites were added: the "Mosque of Córdoba"; "The Alhambra and the Generalife, Granada"; "Burgos Cathedral"; "Monastery and Site of the Escorial, Madrid"; and "Park Güell, Palau Güell and Casa Milà, in Barcelona". Five sites were added in 1985, and another four in 1986. Apart from 1984, 1985, and 1986 (Spain's first three years as a member), 2000 saw the most new sites inscribed, with five that year. As of June 2016, Spain has 46 total sites inscribed on the list, third only to China (52) and Italy (53). Of these 46 sites, 40 are cultural, 4 are natural, and 2 are mixed (meeting both cultural and natural criteria), as determined by the organization's selection criteria.
The Pirineos - Monte Perdido World Heritage Site is shared with France, while the Prehistoric Rock-Art Sites in the Côa Valley and Siega Verde site is shared with Portugal. Besides that, Almadén is inscribed alongside Idrija in Slovenia. Of the 17 autonomous communities of Spain, Castile and León has the most sites, with six exclusive and three shared sites.
Additionally, Spain has established an agreement with UNESCO known as the Spanish Funds-in-Trust. The agreement was signed on April 18, 2002 between Francisco Villar, Spanish Ambassador and Permanent Delegate to UNESCO, and the Director-General of UNESCO, Kōichirō Matsuura. The fund provides € 600,000 annually to a chosen program. Programs include helping other member states, particularly in Latin America, with projects such as nominations processes and assessing tentative sites. Spain served as the chair of the World Heritage Committee in 2008 and 2009, and in 2009 hosted the 33rd Session of the Committee in Seville, Andalusia.