The GR11 is a glorious 820km traverse of the Pyrenees from the Atlantic to the Mediterranean on the Spanish side of the border with France, taking about 47 days to walk. Although it's a serious challenge for experienced hikers, the route is less demanding than the higher-level HRP, sunnier and wilder than the GR10 which runs along the French side, and well waymarked throughout with regular opportunities to find accomodation and stock up your supplies.