Corta Atalaya is the largest open-pit mine in Europe and was at one time the largest in the world. It is located within the city limits of Minas de Riotinto in the province of Huelva, autonomous community of Andalusia, Spain. It is roughly elliptical in shape, 1,200 metres (3,900 ft) long, 900 metres (3,000 ft) wide, and 350 metres (1,150 ft) deep. It was one of the most ambitious projects of the Rio Tinto Group.