Started in 1468 and completed in the 18C, this church has been embellished by a succession of artists including Sangallo, Bramante and Vanvitelli. Its sober and harmonious façade (note the lovely trefoil apse) is heralded by three bronze doors. There is the sacristy of San Marco, decorated with frescoes by Melozzo da Forli, and the sacristy of San Giovanni decorated by Luca Signorelli; all culminates with the Santa Casa at the crossing, sumptuously decorated in carved marble.