Between the Piano d'Erba and the Larian Triangle there is a singular territory that extends in the vicinity of Lake Segrino, this stretch of water was called "Fons Sacer" and already from the time of the Celts and Romans this place was populated by ancient people. What is proposed is an itinerary wandering through time and in particular discovering the Middle Ages when this singular land was rich in towers and castles. It was in fact for its geographic conformation a place of passage and control towards the north since Roman times, with a road leading to the apex of the Larian Triangle where at Bellagio there was a naval fleet that could take garrisons up to the upper lake. Even in the Middle Ages this road route was maintained because of its special strategic and connecting importance. Towers and castles thus arose to guard this pass, and the localities of Longone, Eupilio, Canzo, and Castelmarte still guard several vestiges of this ancient medieval legacy, where castles and towers stood guard for those who had to pass with the obligation to pay a gabella. On this route, visitors will be accompanied to discover stories of dragons, princesses and knights who once populated this strip of "Middle Earth." The Ghita Tower, the castle of Galliano and Corneno, the tower of Longone and the vanished castles of Canzo and Proserpio will come back to life thanks to the tales and stories of the Friends of the Martesana of Erba.