It’s a common enough story in Italy: An ancient ruin — in this case, a tract of Roman road — is discovered during the construction of a building — in this case, a McDonald’s — and puts a halt to the work until the site can be excavated. Rather than fret about lost time and money, McDonald’s decided to sponsor the dig, and it worked with the archaeological authorities to preserve the road, built between the second and first centuries B.C.

As of Tuesday, visitors to the fast-food restaurant, about 12 miles southeast of central Rome, could walk along the 147-foot stretch of road without even having to buy a Big Mac. Many parts of Italy contain subterranean riches, and over the centuries, countless edifices have incorporated or adapted the ruins of previous eras.