The Latin Quarter is the core of the Left Bank — as the south side of the Seine River is known. This has long been the city’s university district. In fact, the University of Paris, a leading university in medieval Europe, was founded here in the 13th century.

Back then the vernacular languages, like French and German, were crude…good enough to handle your basic needs. But for higher learning, academics — like this guy — spoke and corresponded in Latin. Until the 1800s, from Sicily to Sweden, Latin was the language of Europe’s educated elite. And Parisians called this university district “the Latin Quarter” because that’s the language they heard on the streets.

Today, any remnant of that Latin is buried by a touristy tabouli of ethnic restaurants. Still, it remains a great place to get a feel for the tangled city before the narrow lanes were replaced by wide modern boulevards in the 19th century.

The scholarly and artsy people of this quarter brewed up a new rage: Paris’ café scene. By the time of the Revolution, the city’s countless cafes were the haunt of politicians and philosophers, who plotted a better future as they sipped their coffee.

And the café society really took off in the early 1900s, as the world’s literary and artistic avant-garde converged on Paris. In now-famous cafés along Boulevard St. Germain and Boulevard St. Michel, free thinkers like Hemmingway, Lenin, and Jean-Paul Sartre enjoyed the creative freedom these hangouts engendered.

With its café and university scene, Paris had long been a launch pad for bold new ideas. In the 18th century, ground-breaking political and social thinking by French philosophers like Voltaire and Rousseau ushered in the “Age of Enlightenment.” Later, this Enlightenment provided the French Revolution with a philosophical basis, and it gave the American constitution many of its basic principles.

Paris honors its intellectual and cultural heroes with tombs and memorials in its Neoclassical Panthéon. It looks like an ancient temple, but it’s only about 250 years old — from the time of the Enlightenment.

During the Enlightenment, and the Age of Revolution which followed, everything was subjected to what was called the “test of reason”: if it wasn’t logical, it was tossed out. Nothing was sacred. The very notion of royalty was challenged, and churches were turned into temples of Reason.

Even the use of city land for cemeteries — as you learn at the catacombs of Paris — was rejected. The sign reads: “Halt! this is the empire of death.” It kicks off a one-mile hike you won’t soon forget. The anonymous bones of 6 million permanent Parisians line former limestone quarries deep under the streets. In 1785, Paris decided to make its congested city more spacious and sanitary by emptying the cemeteries — which traditionally surrounded churches — into this labyrinthine ossuary.

For decades, priests led ceremonial processions of black-veiled, bone-laden carts into the quarries, where the bones were carefully and artistically stacked — as much as 80 feet deep. Each transfer was finished with a plaque identifying from which church the bones came, and the date they arrived.

While there is history in dem bones, the Carnavalet Museum — filling a lavish old aristocratic mansion — is the best place to sort through the story of Paris.

Pre-Revolutionary France had a government by, for, and of the wealthy. And as the rich got richer and richer, people who lived in fabulous mansions like this became blind to the growing gap between the haves and have nots in their country.

Louis XIV — a.k.a. “the Sun King” — was the ultimate king back when people accepted the notion that a few were born to rule and be rich, while most were born to be ruled and taken advantage of.

Room after room shows the opulence of the upper classes in the age leading up to the Revolution. Louis XIV, who enjoyed the luxury but anticipated trouble, said, “Après moi, le deluge” (after me, the flood).

The heart of the museum features that deluge, which hit when this man, Louis XVI, was king. The French Revolution was kicked off with the storming of the Bastille prison. Supporting the angry masses, the liberal wing of the government took matters into its own hands, declaring it wouldn’t quit until the people had a constitution. It was vive la Nation — liberté, égalité, and fraternité — until the people literally beheaded the king and queen.

The Place de la Révolution (or “Revolution Square”): It was here that the new-fangled guillotine, considered a humane form of execution in its day, was set up. And it was here that Marie Antoinette, Louis XVI, and over 2,000 others were made “a foot shorter at the top.”

According to this painting, it took three to run the guillotine: one to manage the blade, one to catch the blood, and one to hold the head — in this case, of Marie Antoinette — up to the crowd.

Today, Paris’ vast Revolution Square is called Place de la Concorde — “place of harmony.” The guillotine is long gone, and its centerpiece is an Egyptian obelisk.

The king and queen were beheaded by a stark and egalitarian government. But the French love of fine living couldn’t be kept down. The 19th century was a boom time for Paris. The entire city was beautified with grand new boulevards and fancy architecture. It was an exuberant age of money — if you had it, you flaunted it.

From the Place de la Concorde, the Champs-Elysées — once a royal carriageway, now Europe’s grandest boulevard — leads to the Arc de Triomphe. The arch was dedicated to the victory of the people and their republic…the triumph of French Nationalism.