Dedicate your fifth day to visiting some of Spoleto's most significant historic sites. Start with a visit to the Basilica di San Salvatore, a UNESCO World Heritage site known for its beautiful Byzantine mosaics. Then, explore the underground wonders of the Roman House, an archaeological site that offers a glimpse into ancient Roman life. In the afternoon, visit the Palazzo Collicola Arti Visive, a contemporary art museum housed in a historic palace. End the day with a walk along the city walls for panoramic views of Spoleto.