La Verna, the "Blessed Mountain" of Brother Francis, emits a force of attraction which can be felt all over the world. And not just among Christians. Therefore, the journey towards the "raw rock" can be as interesting as the achievement of a goal, especially if it starts from the basilica of Santa Croce in Florence and crosses the entire upper Casentino. Connecting the basilica of Santa Croce to the cliffs of La Verna combines two wonders, one created by man, the other by nature. It's like bringing the daughter to the mother or going up a river to its source. The iter we are about to describe actually follows the royal river of Tuscany, the Arno, almost up to its source on the sides of Falterona. This guide is addressed to pilgrims so it of course avoids paved roads. It searches for paths which patiently follow the territory, without digging out, drilling or bypassing. Precisely the distinctive nature of our Guide is: make the journey of pilgrims and hikers safer and more enjoyable along one of the most interesting Franciscan routes. Wishing "Buon viaggio!" to those who walk on the beautiful trails of the Casentino (it is important to take the first step, the rest comes along by itself), we wish to quote the famous phrase by John Steinbeck (Travels with Charley, 1962): "People don't take trips... trips take people".