Flames jumped up the ornate spire before it collapsed onto the blaze-engulfed roof, sending smoke billowing out into the evening skyline of the French capital. The historic church, located on one of two islands in the middle of the Seine River, had been under renovation and scaffolding had covered much of the top structure. The blaze began around 7 p.m. local time on Monday.

Live television images transfixed viewers around the world and French President Emmanuel Macron postponed a major speech as flames ravaged the cathedral that has towered over Paris for centuries. It had come through long-range German bombardment during World War I and was spared damage during World War II.

French Deputy Interior Minister Laurent Nunez said the building may not be able to be saved and that it’s too early to say what caused the fire. Paris prosecutors have opened an investigation.

“We have structures that aren’t holding so the next hour and a half will be decisive,” Paris Fire Brigade Commander Jean-Claude Gallet told reporters. “We’re not sure of being able to contain the fire from propagating.”

Bystanders were cordoned off from the blaze, with many singing and praying, or standing by in silent disbelief. Thousands of people were evacuated from the building after the fire broke out and hundreds of onlookers remained on the scene as ashes fell onto surrounding streets. There were no reports of fatalities.

“It is eight centuries of history going up in smoke,” said Marion Lacroix, a 54-year-old Parisian. “It’s the heart of the country. I think that in our generation, people won’t see Notre Dame built again. It’s over.”

The flames lapping the famous landmark is just the latest in a string of tragedies to strike the French capital. In 2015, Paris was the site of two of the worst terror attacks in the country’s post-WWII history. Since last November, the city has also been under siege every Saturday as clashes between the so-called Yellow Vest protesters and police have turned violent.

Notre Dame is a major tourist destination, with the number of visitors swelling to as many as 50,000 a day, especially during periods like holy week in the Christian calendar leading up to Easter.

Some 400 firefighters were mobilized to the scene, according to the interior ministry. Extra help from outside the city was headed to the capital to help contain the blaze and helicopters could be seen flying overhead, although weren’t being used to drop water because of the risk the extra weight would lead to further structural collapse.

Paris Mayor Anne Hidalgo wrote on Twitter she was at a loss for words “to express the pain I feel in the face of the ravaging flames. Tonight Parisians and the French mourn this symbol of our common history.”

Macron went to an administrative building near the site after postponing a much-anticipated speech on planned policy measures following the Yellow Vest movement that has rocked the capital.

“Notre Dame is engulfed with flames,” he said on Twitter. “Thoughts are with Catholics and all the French. Like all citizens, I am sad to see this part of us burn.”

Notre-Dame de Paris en proie aux flammes. Émotion de toute une nation. Pensée pour tous les catholiques et pour tous les Français. Comme tous nos compatriotes, je suis triste ce soir de voir brûler cette part de nous.

— Emmanuel Macron (@EmmanuelMacron) April 15, 2019

Even President Donald Trump was following the fire.

So horrible to watch the massive fire at Notre Dame Cathedral in Paris. Perhaps flying water tankers could be used to put it out. Must act quickly!

— Donald J. Trump (@realDonaldTrump) April 15, 2019

Construction got underway in the 12th century, though the current structures are mostly the result of renovations carried out in the 19th century following damage during the French Revolution.

The cathedral was at one time in a state of total disrepair and close to the point of being demolished, but was later saved by Napoleon who himself was crowned Emperor in 1804 inside the cathedral.

The interior of the cathedral is 427 by 157 feet, with its 115-foot-high roof. Two massive early Gothic towers crown the western facade, which is divided into three stories and has its doors adorned with early Gothic carvings and surmounted by a row of figures of Old Testament kings.

“This is horrible,” said Julien Ciprelli, a 19-year-old politics student living in Paris. “‘I saw the smoke from the classroom. I had to come.”