|The BU set commemorates the 25th anniversary of the Treaty of Maastricht and contains a complete set of Spanish euro coins, as well as a 2 euro coin dedicated to the Church of Santa Maria del Naranco.
The church of St Mary at Mount Naranco is a Roman Catholic Asturian pre-Romanesque Asturian architecture church on the slope of Mount Naranco. It was completed in 848 and its structural features, such as the barrel vault — with transverse ribs corresponding one-to-one with contraforts at the exterior, make it a clear precursor of the Romanesque construction. The exterior decorations, as well as the use of stilted arches mark the intended verticality of the composition. It was converted into a church at the end of the 13th century. It was declared a World Heritage Site by UNESCO in December 1985.
The Maastricht Treaty was signed on 7 February 1992 by the members of the European Community in Maastricht, Netherlands. It created the three pillars structure of the European Union and led to the creation of the single European currency, the euro.