I spent this year’s vacation in Corsica mountains walking the half of GR20 trail. See this page for more info about GR20. We hiked only the nothern half from Callenzana to Vizzavona. I had to quit one day early as my shoes transformed into sandals and my big toe had a nail problem. Plus after 9 days in the mountains, I had enough of rocks and was really forward to have a nice meal, hot shower and sleep in decent bed. Photos inside the article.