Las Médulas is the largest gold mine in the world from the time of the Roman Empire, with more than 160 km of canals, mines, and gold panning areas. On this route, we'll venture into the largest gold-washing area in this World Heritage park. A 3 km long valley where a completely artificial river was built to wash the material extracted from the mines and obtain gold. On this route, you'll visit the tailings area that begins at the Sil River from Salas de la Ribera, then head up to the Cueva de la Palombeira, a cave 250 metres long and 7 metres high, the only cave excavated in the rock, and then down through the El Valgón canyon, a 1-kilometer-long limestone canyon that channelled the water from the mine back to the Sil River. An unknown and wild area of the park that you can't miss.