PARIS — The word "Merci" was projected onto the front of Paris' Notre Dame Cathedral as it reopened on Saturday, in thanks for its salvation after a devastating fire that brought the 860-year-old building close to collapse.

The cathedral's bells rang out and the Archbishop of Paris, Laurent Ulrich, struck the doors of Notre Dame three times with his crozier before symbolically reopening the building, as the ceremony started. First responders who helped preserve the Gothic masterpiece and some of those who subsequently restored it received a standing ovation.

"I stand before you to express the gratitude of the French nation, our gratitude to all those who saved, helped and rebuilt the cathedral," President Emmanuel Macron said, adding that with the swift renovation, France had "achieved the impossible".

"Tonight we can together share joy and pride. Long live Notre-Dame de Paris, long live the Republic and long live France."

Five years ago, on the evening of April 15, 2019, dismayed Parisians rushed to the scene and TV viewers worldwide watched horrified as the fire raged through the cathedral, the spire fell and the roof collapsed.

Now, Notre Dame has been meticulously restored, with a new spire and rib vaulting, its flying buttresses and carved stone gargoyles returned to their past glory and white stone and gold decorations shining brightly once again.

Among the dignitaries in attendance were President-elect Donald Trump, along with outgoing First Lady Dr. Jill Biden and Britain's Prince William, among others. Trump sat next to Macron and Macron's wife Brigitte in the front row, while Dr. Biden sat on the other side of Brigitte Macron.

But earlier on Saturday, guests stood and applauded as Ukrainian President Volodymyr Zelenskiy walked into the cathedral, fresh off a trilateral meeting with President Macron and President-elect Trump.

Tesla billionaire Elon Musk, a close adviser in Trump's transition team, also attended, as did France's richest man, Bernard Arnault, as well as Italian Prime Minister Giorgia Meloni and former French presidents Francois Hollande and Nicolas Sarkozy.

France's national anthem, "La Marseillaise", rang out as the ceremony drew to a close as Macron prepared to host Trump and the other dignitaries at a dinner in the presidential Elysee Palace.

Thousands worked on the restoration

Thousands of experts, from carpenters and stonemasons to stained glass window artists, worked round the clock for five years, using age-old methods to restore, repair or replace everything that was destroyed or damaged.

"Notre Dame is more than a Parisian or French monument. It's also a universal monument," said historian Damien Berne, who was also a member of the scientific council for the restoration. "It's a landmark, an emblem, a point of reference that reassures in a globalized world where everything evolves permanently."

The cathedral's first stone was laid in 1163 and construction continued for much of the next century, with major restoration and additions made in the 17th and 18th centuries.

Victor Hugo helped make the cathedral a symbol of Paris and France when he used it as a setting for his 1831 novel "The Hunchback of Notre-Dame", with Quasimodo, the main character, having been portrayed in Hollywood movies, an animated Disney adaptation, and in musicals.

Some Parisians were particularly thrilled by the reopening.

"What does Notre Dame mean to me? This. Look, it's here," said careworker Pascal Tordeux, displaying a tattoo on his arm representing the cathedral. "It means everything."

"I saw the construction every day from my window, the spire being brought down, being brought back. I saw it burn, I saw it rise again. I followed it day by day," said Tordeux, who lives across the river from Notre Dame.

Would-be visitors can now book a free ticket online, on the Cathedral's website. But on Saturday, the first-day bookings could be made for the coming days, all tickets were gone, a message on the site said.

Group visits will be allowed next year, from Feb. 1 for religious groups or from June 9 for tourists with guides. The Catholic Church expects the cathedral to welcome 15 million visitors each year.

So much money poured in for the renovation from all over the world — more than $880 million, according to Macron's office — there are still funds left over for further investment in the building.

In a message read aloud during the ceremony, Pope Francis said it was a day of "joy, celebration and praise."

Weighing in a heated debate on whether visitors should pay to visit the cathedral — which some French politicians have pushed for to help restore other churches — the pope, who was not at the ceremony himself, said in his message that he trusted all would continue to be welcomed for free.

Archbishop Ulrich will celebrate a Mass on Sunday, the first of eight days of Masses devoted to the reopening and focused on thanking, among others, donors who paid for the renovations and firefighters who helped save it. Some of the Masses, including those held this evening at Notre Dame, will be open to the public.

Destroyed by fire

Massive fire engulfs beloved Notre Dame Cathedral in Paris

A massive fire swept across the top of Paris' soaring Notre Dame Cathedral as it was undergoing renovations Monday, collapsing its spire and threatening one of the world's greatest architectural treasures as tourists and Parisians looked on aghast from the streets below.

Contributing: Michel Rose, Ardee Napolitano, Dominique Vidalon, Marco Trujillo and Ingrid Melander

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