This post is dedicated to my friend Gilles Thomas, for his tireless devotion to preserving the work — and honoring the memory — of Charles-Axel Guillaumot.

Suppose you’ve been hired to oversee a vast and vital railroad network. Now imagine that, on the very first day of your new job, one of the trains on your network derails and plows through a house.

Something similar actually did happen to Charles-Axel Guillaumot on Thursday, April 24, 1777.

A few months earlier, one week before Christmas in 1776, a catastrophic event had stunned Paris. According to Graham Robb, in Parisians, An Adventure History of Paris:

… the roofs of the buildings … changed their angle slightly in relation to the skyline. A second later, there was the sound of a giant heaving a great sigh and stretching his limbs. The cattle that had passed through the [Barrière d’Enfer toll] gate panicked and backed into the barrier. … a cloud was billowing up from the road, and the buildings on the street beyond the Rue d’Enfer suddenly came into view. Along the eastern side of the Rue d’Enfer itself, extending … one quarter of a mile, a gaping trench had opened up and swallowed all the houses.”

On April 4, 1777 the young King Louis XVI appointed Charles-Axel Guillaumot to look into the matter. But, because of bureaucratic delays, Guillaumot didn’t actually start work until April 24 — the day of the next major cave-in. It was on this particular spring Thursday that the rue d’Enfer (“Hell Street”) truly earned its name.

Carriages and oxcarts choked the street and crowds of gawkers blocked the view as Charles-Axel Guillaumot arrived at the scene of the cave-in. The air smelled stale — like some long-forgotten, musty attic — as he stepped off his sedan chair in front of the Marquise de Roncet’s house.

The outer walls of the Marquise’s property betrayed nothing unusual, apart from the crowds. But when Guillaumot pulled the Royal Decree from his pocket that granted him access to the courtyard, the scene was anything but usual: The façades of the stables had disappeared, and before them stretched a gaping hole.

An ordinary man might have resigned his post on the spot; but Charles-Axel Guillaumot was anything except ordinary.

Guillaumot’s parents were French, but — because his father was a traveling merchant — he was born in 1730 in Stockholm, Sweden. According to Graham Robb,

the accident of his birth … had disqualified him from every scholarship that was open to Frenchmen. He had been forced to fight his way out of obscurity with nothing but genius and determination.”

He left Paris to study architecture in Italy. And when Italy opened its artistic competitions to all of Europe in 1750, Charles-Axel Guillaumot entered — and won the architectural Prix de Rome. He was only 20 years old.

He returned to Paris and married a Mlle. Le Blanc (who happened to be the royal chief architect’s daughter). But in spite of his talent, education and social status, prestigious work continued to elude Guillaumot. By the time Louis XVI appointed him in 1777, “his talent for shoring up other men’s shoddy work had brought him [only] lucrative but inglorious commissions,” according to Graham Robb.

Nevertheless, all of Guillaumot’s years of study and experience coalesced the moment he looked into the sinkhole in front of the Marquise de Roncet’s stables. He knew exactly what needed to be done.

The sinkholes were not the work of the Devil, as many Parisians thought, but the result of long-abandoned limestone quarries under Paris. As the city had expanded, construction and traffic had stressed some of the underground caverns to the point of collapse.

With the help of some 400 workers, Guillaumot set out immediately to map and consolidate the old quarries. According to Graham Robb,

For the first phase of consolidation, he divided his workers into three teams. The ‘Excavation’ team, composed of migrant workers, was to clear the galleries of rubble.”

Some portions of the Cochin quarry show how the tunnels likely looked right after being cleared of debris.

Then the ‘Masonry’ team would reinforce [the walls and] the roof with pillars, using the stone that had been dug out by the excavators.”

The reinforced walls are typical of Guillaumot’s “consolidation” efforts.

The photo below shows arches that were built to reinforce the site of a cave-in (labeled “fontis” in the left side of the image).

But not all of the repairs to the Cochin quarry were as elegant or ornate. I skittered through this tight passageway quite quickly, just in case …

Finally, the ‘Cartography’ team would create a map of the underground labyrinth on a scale of 1:216 — which meant that the map of abandoned quarries would be more detailed than any map that had ever been produced of the streets of Paris.”

Guillaumot devised a system that identified the quarry section, the inspector’s initial(s), and the date of inspection or consolidation. (And no matter how many times I see Guillaumot’s stylized “G,” I still get a chill down my spine.)

This vital and meticulous work continued until 1792, when Guillaumot was imprisoned for two years during the French Revolution — partly because of his royal appointment, and partly because of a rival architect’s scheming. But when he was released in 1794 he went right back to work at his old post, and also took over as the head of the Manufacture des Gobelins.

He and his men would go on map and consolidate some 300 kilometers (about 180 miles) and a mind-boggling six million cubic meters of quarries in a masterpiece of engineering and architecture that has never been equaled.

He held his post as Chief Inspector of the quarries until his death in Paris on October 7, 1807. He was buried in the Cimitière Sainte-Catherine, which — ironically — was emptied into the underground municipal ossuary he helped establish. Today his remains rest somewhere among the six million other Parisians who ended up in the Catacombes.

It would take almost a century of work after his death to complete Paris’ underground rescue — but sadly, very few people remember his name today.

Perhaps that will soon change, however. In April of 2013 Paris’ City Council voted in favor of naming a street after him, and one proposal calls for an esplanade in the 14^th arrondissement, near the entrance to quarry inspection agency he founded.

May he always be remembered as the man who saved Paris.

My thanks again to Gilles Thomas for his extraordinary work in keeping Paris’ history alive — and making it so vivid.

Additional sources:

Gilles Thomas

Le Parisien

Radio France International

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^{Text and images © Heather Munro.}