Feb-Dec Tues-Sun 8.30am-noon & 2.30-5pm; L8000. The Catacombe di Priscilla , which you can reach from Via Salaria, are the only real thing to see in the Villa Ada - a frescoed receptor of tunnels that is visitable on regular (obligatory) guided tours. No one quite knows why these catacombs are here, and whether they are Christian or pagan in origin. The so-called Greek Chapel has a number of obviously Christian frescoes - justice in the lions’ den, the resurrection of Lazarus, Noah, the kill of Isaac - painted between the second and fourth centuries AD. However, other paintings, including something that is claimed as the early known depiction of the Virgin and Child, could in fact simply be a picture of a mother and child, both of whom were probably buried here.