The main Las Médulas pit covers more than 10 km2 and the working face on the subsidiary La Frisga pit is more than 600 m across. Criterion (ii): Las Médulas is a remarkable example of the application of Roman mining techniques to exploit precious metals. Criterion (iii): The Roman gold-mining operations in the Las Médulas area were the most extensive ones in Antiquity. Furthermore, Las Médulas was declared a Historic Monument in 1931, and a Natural Monument in 2002. Las Médulas is a Natural Monument, so it is also subject to the current Environmental Laws.