PARIS - The fire that tore through Notre Dame cathedral was probably caused by accident, French prosecutors said on Tuesday after firefighters doused the last flames in the ruins overnight and the nation grieved for the destruction of one of its symbols.
More than 400 firemen were needed to tame the inferno that consumed the roof and collapsed the spire of the eight-centuries-old cathedral. They worked through the night to extinguish the fire some 14 hours after it began.
The Paris Fire Brigade said Tuesday the structure of the famed Notre Dame cathedral has been saved, along with the site's main works of art, after 400 firefighters spent more than nine hours battling a fire that caused massive damage.
The building's two iconic towers and stone structure were standing Tuesday, but absent were the 12th-century cathedral's roof and spire, which collapsed in the blaze.
Paris Mayor Anne Hidalgo thanked firefighters and police officers for helping to save holy objects and major works of art from the cathedral.
Merci aux @PompiersParis, aux policiers et aux agents
Paris public prosecutor Remy Heitz said there was no obvious indication the fire was arson. Fifty people were working on what would be a long and complex investigation. One firefighter was injured but no one else was hurt in the blaze which began after the building was closed to the public for the evening.
From the outside, the imposing bell towers and outer walls, with their vast flying buttresses, still stood firm, but the insides and the upper structure were eviscerated by the blaze.
Firefighters examined the gothic facade and could be seen walking atop the belfries as police kept the area in lockdown.
Investigators will not be able to enter the cathedral's blackened nave until experts are satisfied its stone walls withstood the heat and the building is structurally sound.
The fire swiftly ripped through the cathedral's timbered roof supports, where workmen had been carrying out extensive renovations to the spire's wooden frame.
Is there anything firefighters could have done to control the blaze that tore through Paris' historic Notre Dame Cathedral sooner?
Experts say the combination of a structure that's more than 850 years old, built with heavy timber construction and soaring open spaces, and lacking sophisticated fire-protection systems left firefighters with devastatingly few options Monday once the flames got out of control.
"Very often when you're confronted with something like this, there's not much you can do," said Glenn Corbett, a professor of fire science at John Jay College.
Fire hoses looked overmatched
The Paris prosecutor has opened an investigation into "involuntary destruction by fire." Police on Tuesday began questioning the workers involved in the restoration, the prosecutor's office said.
Hundreds of stunned onlookers had lined the banks of the Seine river late into the night as the fire raged, reciting prayers and singing liturgical music in harmony as they stood in vigil.
Some kneeled, some folded their hands to make silent entreaties. Others sang with their eyes focused on the sky that had gone from blue to yellow and orange, and filled with acrid smoke.
In an impromptu act of togetherness and hope, Parisians and people just visiting France's charismatic capital came together to pray for Notre Dame as a fire quickly advanced through the cathedral.
The blaze that engulfed Notre Dame brought memories and sorrow to people around the world who had seen or dreamed of seeing the church known for its sculpted gargoyle guards and place in literary history.
"Yesterday we thought the whole cathedral would collapse. Yet this morning she is still standing, valiant, despite everything. It is a sign of hope," said Sister Marie Aimee, a nun who had hurried to a nearby church to pray as the fire spread.
It was at Notre Dame that Napoleon was made emperor in 1804, Pope Pius X beatified Joan of Arc in 1909 and former presidents Charles de Gaulle and Francois Mitterrand were mourned.
Messages of condolence flooded in from around the world.
Pope Francis, the leader of the Catholic Church, was praying for those affected, the Vatican said, adding: "Notre Dame will always remain - and we have seen this in these hours — a place where believers and non-believers can come together in the most dramatic moments of French history."
Britain's Queen Elizabeth expressed deep sadness while her son and heir Prince Charles said he was "utterly heartbroken."
Vow to rebuild
President Emmanuel Macron promised to rebuild Notre Dame, considered among the finest examples of European Gothic architecture, visited by more than 13 million people a year.
Notre Dame is owned by the state. It has been at the center of a years-long row between the nation and the Paris archdiocese over who should finance badly needed restoration work to collapsed balustrades, crumbling gargoyles and cracked facades.
It was too early to estimate the cost of the damage, said the heritage charity Fondation du Patrimoine, but it is likely to run into the hundreds of millions of dollars.
The rival billionaire owners of France's two biggest luxury fashion empires, Francois-Henri Pinault of Kering and Bernard Arnault of LVMH, pledged 100 million euros and 200 million euros to the restoration respectively. Oil company Total pledged 100 million. The city of Paris said it would provide 50 million.
Paolo Violini, a restoration specialist for Vatican museums, said the pace at which the fire spread through the cathedral had been stunning.
"We are used to thinking about them as eternal simply because they have been there for centuries, or a thousand years, but the reality is they are very fragile," Violini said.
The company carrying out the renovation works when the blaze broke out said it would cooperate fully with the investigation "All I can tell you is that at the moment the fire began none of my employees were on the site. We respected all procedures," Julien Le Bras, a representative of family firm Le Bras Freres.
Officials breathed a sigh of relief that many relics and artworks had been saved. At one point, firefighters, policemen and municipal workers formed a human chain to remove the treasures, including a centuries-old crown of thorns made from reeds and gold, and the tunic believed to have been worn by Saint Louis, a 13th century king of France.
"Notre Dame was our sister, it is so sad, we are all mourning," said Parisian Olivier Lebib. "I have lived with her for 40 years. Thank God that the stone structure has withstood the fire."