The GR 20 is a GR footpath that crosses the Mediterranean island of Corsica running approximately north-south, described by the outdoor writer Paddy Dillon as "one of the top trails in the world".
The whole trail is about 180 km long with 12,000m of elevation gain, clearly waymarked throughout, the walk for most of the 10,000-20,000 hikers per year takes around 15 days. The trail is considered to be the most difficult of all the GR routes and consists of two parts: the northern part, between Calenzana and Vizzavona and the southern part, between Vizzavona and Conca.
Vizzavona is considered the middle as there is a train station, and therefore is an accessible point for walkers beginning or ending a walk consisting of half the route.
Wikipedia https://en.wikipedia.org/wiki/GR_20
Address Place du Monument, Calenzana 20214, France
Coordinates 42°30'27.144" N 8°51'20.005" E