The typical street in ancient Italian cities was built of paving stones of basalt, a rugged igneous rock. The road above is the first thing noticed upon entering the ancient city of Pompeii. The center of the road is raised to allow water to run off into the gutters. The small white stones, ingeniously inserted randomly between the large stones, allowed people and animals to see the road after dark. Sidewalks, provided on each side of the road for pedestrians, also often contained some white tiles or small white stones to aid nighttime visibility.
Out of view to the right side of the above photo once stood the Temple of Venus, the patron goddess of Pompeii. There's not much to see there now. The temple was heavily damaged in the earthquake of 62 A.D. and not restored before it was ruined in the eruption of 79. And during World War II its excavation was demolished by an Allied bomb that missed its target. (There are rumors that the Allies were hoping to explode a bomb in the crater of Vesuvius to set off an eruption.)