GR 10 is a French GR footpath, or hiking trail, that runs the length of the Pyrenees Mountains. It roughly parallels the French–Spanish border on the French side. Those attempting the entire trail often choose to walk it from west to east, from Hendaye on the Bay of Biscay to Banyuls-sur-Mer on the Mediterranean Sea, but it can also be traversed east to west. Description Hiking the entire route is estimated to take around 52 days for hikers who are physically fit and used to mountain hiking. Some stretches involve a lot of ascending and descending, including a few one-day sections that can climb and then descend , but the GR 10 is a hiking trail, and there is no actual mountain climbing involved. The trail covers a distance of , with of ascent and, given the coast-to-coast nature of the route, the same descent. Lodging along the route that cater to walkers include hotels, gîtes d'étape, and very basic mountain refuges. Camping is only necessary for two or three nights in the Ariège section. Some walkers walk one section of the trail at a time, completing the route over several visits. The trail is well marked with red and white painted blazes. It appears on all regional maps, including on Michelin roadmaps. The route is within the area shown by the Editions Sud-Ouest Rando éditions range of maps (numbers 1–11), which are based on French Institut Géographique National 1:50,000 scale maps. Parts of the route, especially around towns and villages, change from year to year, so walkers should carry the most recent editions of the maps and guides. A number of sections include alternative routes of a less demanding nature. Some alternatives offer more scenic choices, for example the alternative route from Cauterets to Luz-Saint-Sauveur takes in Pont d'Espagne, the Refuge Oulettes de Gaube, the Refuge Baysellance, Gavarnie, Gedre and Pragneres, and offers more spectacular mountain scenery. Another notable section is near the village of Etsaut, where the route follows the Chemin de la Mâture, a track carved into a sheer cliff face. This path was created in the 18th century to facilitate the transport of tree trunks destined to be made into masts for French warships. There are four very detailed guide books (in French) describing the GR 10. These are published by the Fédération Française de la Randonnée Pédestre (French Hiking Federation). These guide books can be