After a night of partying on a yacht in the harbor at Villefranche-sur-Mer, three young couples decided to come ashore for breakfast.

They tied their dinghy up to a small dock and chose a café on the promenade. They ordered espressos, croissants, and champagne.

On a dare, one of the young women ran to the end of the dock and dove into the harbor. Her companions cheered. Not to be outdone, her boyfriend followed suit.

As they clambered onto the dock, an employee of a harbor-cruise company informed them diving from the company’s dock and swimming in the harbor were not allowed.

The boyfriend resented being told what he couldn’t do. The two argued. Quickly, tempers flared.

The boyfriend shoved the cruise employee into the water. His mates pulled him out and confronted the partiers. A larger fight erupted between the two groups, as punches were thrown by both sides.

On the first day of my high-school Latin class, Mrs. Duncan declared (as did Julius Caesar before her), “Gallia est omnis divisa in partes tres.” Translation: “Gaul is a whole divided into three parts.”

Gaul? It was Greek to me.

Caesar conquered the three parts of Gaul between 58 and 50 BCE. Millions were killed or enslaved during the invasion.

The region known to Caesar as Gaul is now France, Belgium, and parts of Italy, Germany, and Switzerland.

The conquerors and the conquered proceeded to romanize the place. On a recent visit to France, I saw lots of evidence of their public projects.

My first stop was Reims (pronounced to rhyme with taunts), a city in the former province of Champagne in northeast France.

Founded around 18 BCE by a Gallic tribe, Reims became the second largest city in Roman Gaul with a population of over fifty thousand. Its residents enjoyed numerous amenities, including an aqueduct, marketplace, arena, theater, temples, and baths.

Nothing remains of these monuments above ground, except the mammoth Porte de Mars, the last remaining entry gate into the city. Below the surface, however, it’s another story, best told while the champagne chills.