Archaeological site of la Piedra Escrita Nature · Cenicientos, Sierra Oeste, Madrid Located in the municipality of Cenicientos, southwest of Madrid, it is a granite monolith about 7 metres high and 9 metres in circumference. Its front face bears a semicircular niche with a relief of three figures in Roman togas and an inscription that for centuries was read as medieval, with the text «a las tres Marías»; in 1995 the epigraphist Alicia M. Canto recognised beneath the retouching a Roman votive dedication to the goddess Diana, so the monument is interpreted as an ancient altar or rock-cut shrine, and it has also been suggested that it marked the Roman border between Hispania Citerior and Lusitania. The Comunidad de Madrid declared it a Bien de Interés Cultural (Spain's highest level of heritage protection), as a zone of archaeological interest, in August 2021. Photo: Wikipedia / Wikimedia Commons (CC BY-SA) What to see and do in Cenicientos