Just below the piazza is the picturesque Porta all’Arco. Walk through it to look at the far side of the arch: the upper section dates from Roman times, but the large blocks on either flank were part of the original Etruscan city gate, erected in the 7th or 8th century B.C. If we can see it today, it is thanks to the local citizens who buried it in stones in 1944, to keep the Nazi Army from blowing it up as a means to stop the advancing Allies.