Paris mourned as the Notre Dame Cathedral burned. 

In the aftermath of a devastating fire that ravaged Paris' historic Notre Dame Cathedral, French President Emmanuel Macron vowed to rebuild the Parisian landmark. Experts now plan to fortify what's left of the structure, and donations have already started coming in from French philanthropists.

It took nine hours to extinguish the massive fire that broke out Monday evening. Over 400 firefighters took part in the effort to bring the fire under control, eventually putting it out altogether in the early hours of Tuesday.

Though fire crews initially said they "may not be able to save Notre Dame," they were able to preserve the main structure including the outer walls and the two bell towers. Photos from inside the cathedral taken Tuesday morning showed debris still smoldering around the altar.

People in France and around the world mourned the damage, including the loss of the 850-year-old building's iconic spire, as well as part of the roof that collapsed.

#intervention Retour en images sur le feu à #NotreDame de Paris qui a mobilisé près de 400 pompiers. pic.twitter.com/O9ELwENcoY

The fire started shortly after the cathedral closed around 6:45 p.m. local time, and grew quickly in windy conditions. The narrow streets, the heat of the flames and the Parisian landmark's positioning along the River Seine made it difficult for firefighters to get closer.

At around 7:53 p.m., the spire fell amid the flames. Less than 15 minutes later, part of the roof collapsed, Reuters reported. The island where the cathedral is located, Paris' Ile de la Cité, was evacuated just before 8:30 p.m. 

"Everything is burning, nothing will remain from the frame," Notre Dame spokesperson Andre Finot told CBS News shortly after the blaze began.

Though President Donald Trump tweeted that "perhaps flying water tankers could be used to put it out," the civil defense agency of the French government responded that firefighters are using all means to combat the blaze, "except for water-bombing aircrafts which, if used, could lead to the collapse of the entire structure of the cathedral."

Hundreds of firemen of the Paris Fire Brigade are doing everything they can to bring the terrible #NotreDame fire under control. All means are being used, except for water-bombing aircrafts which, if used, could lead to the collapse of the entire structure of the cathedral.

Valérie Pécresse, the president of the Île-de-France region in which Paris lies, confirmed Tuesday that the fire was an accident, although officials have not elaborated on the exact cause. Paris police said it may be linked to the $6.8 million renovation efforts underway. 

No deaths have been reported, but one firefighter was reportedly seriously injured. The final damage estimate is likely to be extensive.

Images of the fire quickly swept the globe on social media. And in Paris, France 24 reported, people gathered and to sing Ave Maria and Catholic hymns.

"Our Lady of Paris in flames. Emotion of a whole nation. Thought for all Catholics and for all French. Like all our countrymen, I'm sad tonight to see this part of us burn," Macron tweeted. France 24 reported that Macron is treating the fire as a national emergency.

In a tweet, Paris Mayor Anne Hidalgo said firefighters were working to control the flames from the "terrible" fire and she urged residents and visitors to respect the security perimeter. 

Un terrible incendie est en cours à la cathédrale Notre-Dame de Paris. Les @PompiersParis sont en train de tenter de maîtriser les flammes. Nous sommes mobilisés sur place en lien étroit avec le @dioceseParis. J'invite chacune et chacun à respecter le périmètre de sécurité. pic.twitter.com/9X0tGtlgba

Much like after the terrorist attacks on Paris in 2015, politicians, religious leaders and ordinary citizens from around also tweeted statements of support. 

"The Holy See has seen with shock and sadness the news of the terrible fire that has devastated the Cathedral of #NotreDame, symbol of Christianity in France and in the world." @AGisotti pic.twitter.com/cRjUxkxRwa

Notre Dame is one of the world’s great treasures, and we’re thinking of the people of France in your time of grief. It’s in our nature to mourn when we see history lost – but it’s also in our nature to rebuild for tomorrow, as strong as we can. pic.twitter.com/SpMEvv1BzB

While the Gothic cathedral, which dates from the 12th century, is a masterpiece itself with its flying buttresses, breathtaking stained glass windows and carved gargoyles, inside its walls are priceless Catholic relics and artifacts, paintings, statues and other precious artwork. Fortunately, some of the the treasures were safely retrieved as the fire unfolded, including a centuries-old crown of thorns made from reeds and gold. And just days ago, copper statues representing the 12 apostles and four evangelists were removed for cleaning as part of the restoration project. 

The cathedral's facade has been the subject of countless paintings and its soaring form also inspired Victor Hugo's famous novel, Notre-Dame de Paris or The Hunchback of Notre Dame. Aside from being one of the most important religious sights in France, it's also a symbol of Paris and one of the city's most visited monuments.

It's too soon to say when restoration on the cathedral will begin. For now, if you want to visit or relive a trip there, check out these virtual tours both inside the majestic halls and from a birds-eye view of the timeless architecture. 

Originally published April 15, 1:09 p.m. PT.Updates at 3:50 p.m. PT, 11:52 p.m. PT and 4:09 a.m. PT: Adds more details.Update April 16 at 6:32 a.m. PT: Adds more details.

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