A police officer was shot dead beside Notre-Dame in 1944

A cathedral square hides three older churches underneath

You are standing on the parvis of Notre-Dame, at Point Zéro, the brass star from which every road distance in France is measured. Somewhere within a few paces of this mark stood the church of Sainte-Geneviève-des-Ardents, burned down centuries ago, itself named for a plague once believed cured by the saint's relics. Before either building rose, this same ground carried the Cathedral of Saint Étienne, a fourth-century basilica whose foundations still lie beneath the paving stones underfoot, demolished only when the builders of Notre-Dame needed the space in 1163.

Forty-one metres from where you stand, a police officer named André Perrin was shot dead by SS forces on 19 August 1944, in the fighting that broke out across the island during the liberation of Paris — one of several such killings marked on plaques scattered around this square.

The square itself, forty-five metres away, only took its open, modern shape after the medieval warren of houses and lanes around the cathedral was cleared in the nineteenth century. What you see now — the wide parvis, the point zéro disc, the long sightline to the cathedral's west front — is a nineteenth-century stage set laid over more than a thousand years of buried churches, palaces, and the island's oldest Christian ground.

The cathedral floor held poets, clergy and a suicide

The ground beneath Notre-Dame, directly ahead of where you stand, gave up more than a hundred burials when restorers went in after the 2019 fire. Clergy and laypeople had been laid under the cathedral floor across centuries, but two lead sarcophagi stood apart: one held Canon Antoine de La Porte, dead in 1710, and the other the Renaissance poet Joachim du Bellay, buried since 1560 and only identified more than four hundred years later.

Inside the same building, in 2013, a man died by gunshot at the main altar — the first suicide recorded there in decades, and a jolt of violence inside a space built for the opposite.

Behind the cathedral, in the nineteenth century, Paris put its dead on public show. The rebuilt Paris Morgue stood deliberately close to Notre-Dame so passersby could help identify corpses; bodies were laid on refrigerated slabs behind glass, and as many as fifty spectators at a time filed past to look, treating the dead as a free attraction until the practice was finally ended.

Closer to the surface of ordinary memory, a man attacked a police officer with a hammer just outside the cathedral in June 2017. Officers shot him; a terrorism investigation followed. It was one more violent afternoon on a parvis that has absorbed a great many of them.

Under all of it, quite literally, lies Lutetia's own burial ground. A Gallo-Roman necropolis at Saint-Jacques, first found in the nineteenth century and turned up again by excavation work in 2023, held some fifty graves over two thousand years old — the resting place of the town that became Lutetia, long before anyone thought to build a cathedral on this island at all.

Viking sieges and Occupation gunfire both struck this island

Two Viking sieges came up the Seine and broke against this island — one in 845, led by a chieftain some have tied to the legend of Ragnar Lodbrok, and a second, far larger, in 885–886, when hundreds of ships and thousands of men tried to take Paris and failed, a defense credited with cementing the city's strategic importance for a thousand years afterward.

A short walk north, the Conciergerie and its clock tower, the Tour de l'Horloge, built in 1370–71, mark the old royal palace on the Île de la Cité — a building that later became the antechamber to the guillotine during the Revolution, holding Marie Antoinette among thousands of others before their trials.

The plaques multiply as you move around the island: gardiens de la paix cut down street by street in the August 1944 uprising against the German occupation — Marcel Ternard, Francis Maurizot, others — each marking almost exactly where they fell, a week-long street battle fought house to house before Leclerc's armored division arrived.

Southwest, in the Square René-Viviani, stands the oldest planted tree in Paris, a black locust put in the ground in 1601 and still alive — a rare living thing older than most of the stone around it.

An outcrop in the Seine decided where Paris grew

Under the paving and the buried churches lies a much older layer: Eocene-era siltstones, marls and clays laid down when this basin was a shallow sea, later overlaid by the sands and gravels the Seine itself deposited as it cut and shifted its channel. The island exists at all because the river once split around a firm outcrop of this ground — the reason Paris grew here rather than somewhere else along the Seine.

A short walk southwest, the Thermes de Cluny preserve the vaulted frigidarium of Roman Lutetia's public baths, among the best-surviving Gallo-Roman ruins north of the Alps — solid evidence of the town that grew on this river crossing two thousand years before Notre-Dame's first stone was laid.