Having visited a number of Catholic, Christian, Moslem and buddhist churches, temples, mosques and basilicas, to me, there is no more genuinely spiritual, holy site than the dual churches of St. Francis, in Assisi, the home of the revered 12th-Century Catholic saint, particularly the lower half of the Cathedral. There is a hushed reverence that descends on you, without anyone needing to ask, when you walk into this edifice. One is truly in the presence of a state of grace.
We also spent time walking around the ancient town of Assisi above the cathedrals, including the ruins of the old fortress, the Rocca Maggiore.