route descriptions give all the information required and there are stunning photographs to inspire you along the way. Corsica is a mountainous island in the Mediterranean and its GR20 is one of the greatest adventure treks in Europe. It is reputed to be the toughest waymarked trail of all the GR routes. An ambitious route for fit and agile walkers, it covers 190km in about two weeks as it makes a complete traverse through the high mountains, negotiating magnificent mountain terrain and following the rocky central spine of Corsica across the whole length of the island.