Sotón Pit Monument · San Martín del Rey Aurelio, Nalón, Asturias The Pozo Sotón, between El Entrego and Sotrondio, in San Martín del Rey Aurelio, began to be sunk in 1918 by Duro Felguera to supply the blast furnaces of La Felguera, and the complex was completed in 1921. It is the only one in the Nalón basin to retain two headframes, joined by the «réter», a large iron structure in a style akin to that of the Eiffel Tower, dating from the 1920s. It remained active until its closure in 2014, the year it was declared a Bien de Interés Cultural (Spain's highest level of heritage protection), and today it houses the mining experience and memory centre, with a gallery open to visitors and a memorial to the workers who died. In 1962, during the great Asturian miners' strike, Carlos Hugo de Borbón worked there under a false name until he was discovered and arrested. Photo: Yandrak (CC BY-SA 4.0) What to see and do in San Martín del Rey Aurelio