Grutas de Mira de Aire

The Mira de Aire Caves, located in Mira de Aire, in the municipality of Porto de Mós, open to the public part of the underground world of the Gruta dos Moinhos Velhos, in the Estremenho Limestone Massif. The first documented descent took place on 27 July 1947; in 1955, the site was classified as a Property of Public Interest, and on 11 August 1974 it received its first visitors. The cave is the result of the slow action of rainwater on limestone, which opened galleries and shafts and formed stalactites, stalagmites and columns. With 11 known kilometres and only part open to visitors, the municipality presents them as the largest tourist caves in Portugal. Along the underground route, lighting highlights chambers, limestone forms and water, with names such as the Organ, the Black River and the Great Lake. In 2010, they were voted one of Portugal’s 7 Natural Wonders.