Spain, having joined the UN on 14 December 1955, participates in ECE, ECLAC, and all the non-regional specialized agencies. Spain became a full member of the OECD in 1959. In June 1970, Spain signed a trade agreement with the EU calling for a mutual reduction of tariffs over a six-year period; the nation became a full member of the EU in 1986. Spain is also a member of the Council of Europe. The entry of Spain into NATO was approved in 1982 and confirmed by referendum in 1986.
In the 1970s, accords for double nationality, cultural assistance, and technical cooperation were signed with the majority of Latin American countries. Spain has observer status in the OAS and the Andean Pact. In June 1975, Madrid was selected as permanent headquarters for the World Tourism Organization. Five years later, Madrid became the seat of the Conference on Security and Cooperation in Europe. Spain is a signatory of the Law of the Sea and a member of the WTO.