Corta Atalaya Monument · Minas de Riotinto, Cuenca Minera, Huelva One of the largest open-pit mines in Europe, worked by the Rio Tinto Company Limited until its closure in 1992; a monument on a colossal scale to a century and a half of copper mining. cierre en 1992 Photo: Benjamín Núñez González (CC BY-SA 4.0) What to see and do in Minas de Riotinto