The Cares Gorge (Garganta del Cares) is the most celebrated walking route in the Picos de Europa and one of the most dramatic gorge hikes in Spain. The trail follows a narrow path carved into the cliff walls of a limestone gorge roughly 1,000 metres deep, running 12 kilometres from the village of Caín in León to Poncebos in Asturias (or the reverse). The path stays high on the gorge wall throughout, with the Cares river far below and the Urrieles peaks rising above.
The route is technically straightforward — no technical equipment needed, no serious scrambling — but the exposure is significant at several points, and the path narrows to less than a metre in places where it is cut directly into the vertical rock face. The most challenging aspect is the sheer number of other hikers in summer. The gorge is genuinely best done in May, June, September, or October, when crowd levels are manageable and the light is not as harsh. Allow 4–5 hours for the full traverse (one direction). Transport between the two trailheads requires advance planning — taxis and buses serve the area in summer.