San Quirico d’Orcia grew up around the medieval village of Osenna. It still retains its medieval planning structure. In the center it is possible to visit the Collegiate Church of Saints Quirico and Giulitta, the Palazzo Pretorio, the Palazzo Chigi and Santa Maria di Vitaleta. The Horti Leonini, with its formal gardens, hosts exhibitions of contemporary sculpture. don’t miss the Rose Garden. Bagno Vignoni Continuing south on the Cassia you arrive at Bagno Vignoni, a spa center founded in the Middle Ages and famous for its “water square”. On the slope that descends towards the river, the Parco dei Mulini is an interesting testimony to medieval hydraulic construction and the techniques for exploiting the power of water.