The GR 20 is a GR footpath that crosses the Mediterranean island of Corsica running approximately north-south, and known as one of the top trails in the world. The whole trail is about 180 km long, clearly waymarked throughout, the walk for most people takes around 16 days. The trail is usually considered as 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. From Vizzavona, the train can be taken to Bastia or Ajaccio.