A French priest was among the firefighters who ran into Notre Dame cathedral as it burned and rescued some of its most valuable artefacts.
Along with firefighters, who fought valiantly to save the structure, Jean-Marc Fournier, the chaplain of the Paris Fire Brigade, ventured into the building as the flames began to engulf the roof.
In the space of just 66 minutes, emergency services rushed to save precious items holed up inside the 850-year-old cathedral.
The first alarm sounded at 6.20pm local time (5.20pm BST), which silenced the priest and a few hundred worshipers inside the cathedral.
Johann Vexo, an organist who has played at Notre-Dame for 15 years, was performing for Monday Mass in the organ loft when he heard the alarm.
He says "everyone was immobilised by shock for maybe a minute," before he went home, oblivious to the flames that would soon engulf his beloved cathedral.
He says he got home, looked out of his window and saw the "terrible, unbelievable" image of the cathedral surrounded by smoke.
The rear doors opened and within a few minutes, the cathedral was empty, he told Ouest-France newspaper.
It appeared at first as if the fire may have been a false alarm, but then a second fire detector went off inside Notre Dame and the fire became visible.
The fire did not seem as if it would spread throughout the building.
Across the Seine River, Paris mayor Anne Hidalgo glanced out of city hall and made her way to the structure.
She said: “I came here and felt powerless as the flames overtook the cathedral."
Sombre onlookers dotted the stone walkways that line the river. They wept as flames overtook the rooftop spire.
Below it, nestled deep in the cathedral, was the treasure chest, keeper of Notre Dame’s most sacred relics.
Firefighters cracked the chest open, pulling out the Crown of Thorns revered as the one worn by Jesus Christ at his crucifixion.
Made of rushes wrapped into a wreath and tied with gold filament, it had been kept under glass since 1896.
The tunic of St Louis, believed to have belonged to King Louis IX, came out of the chest along with fragments of the cross and a nail, said Patrick Chauvet, rector of Notre Dame Cathedral.
The relics were safe.
Then came the artwork.
“We had to get them, in the smoke, as debris was falling, to protect them,” General Jean-Claude Gallet of the fire brigade told BFM television.
The 19th-century spire, that was the masterpiece of Eugene Emmanuel Viollet-le-Duc and his post-Revolutionary restoration, broke apart and fell through the nave, taking with it the three relics sealed inside in 1935.
The sky above the cathedral flamed orange, and the fire lurched toward Notre Dame’s iconic towers, then slipped inside.
As darkness fell, 20 firefighters climbed inside the two towers “at great risk to their lives, to attack the fire from the inside and save the building,” said Laurent Nunez, deputy interior minister.
The majority of the priceless artifacts were saved.
Paris's fire chief said the rest of the structure, including the cathedral's twin bell towers, had been saved.
It had been within 30 minutes of collapse.
It took another 10 hours longer for the last flames to be put out.
The spire's bronze rooster, long a symbol of France, was found on Tuesday, deformed by the heat but recognisable nonetheless.
“Beyond emotion, beyond words, beyond tears,” Christophe Castaner, France’s interior minister, said on Tuesday as he visited the cathedral, “What I want to express is the pride of the men and women who committed to saving Notre Dame.”