Notre Dame, the cathedral that serves as one of Paris’s most beloved and emblematic monuments, is on fire. According to the New York Times, the blaze began around 6:30 p.m. local time, when tourists were urgently rushed out of the building. While André Finot, a spokesman for the cathedral, told the Times that the cause of the fire is currently unknown and that no one has been hurt, damage to the building appears catastrophic. One of Notre Dame’s iconic 19th-century spires collapsed as onlookers groaned and wept; since we began writing this post, the roof has collapsed. Crowds have surrounded the building to pray, cry, and sing hymns.

CNN reports that over 400 firefighters have been dispatched to fight the blaze, but that they may be unable to save the cathedral (they spoke with Jean-Claude Gallet, commander general of the Paris Fire Brigade, who said that the next hour and a half are “crucial” when it comes to saving the structure). Originally built in the 12th century, Notre Dame houses several relics sacred to Catholics; NBC News reports that relics from Saint Genevieve and Saint Denis may have been lost, alongside a relic believed to be from Jesus Christ’s crown of thorns. Update: NBC News confirms that authorities now believe that the cathedral has been save from "total destruction."

Notre Dame is visited by a reported 30,000 people a day and 13 million people per year. Its destruction represents a global cultural loss.

“This is just horrible,” Mohamed Megdoul, 33, a film producer and witness to the fire told the Times, speaking through tears. “A thousand years of history which is being wiped away. This belonged to the whole world, and now it is disappearing.”

French President Emmanuel Macron expressed his grief on Twitter. "Notre Dame of Paris in flames,” reads an English translation of his statement. “Emotion for a whole nation. Thoughts for all Catholics and for all French. Like all our countrymen, I'm sad tonight to see this part of us burn.”

Other political figures, including Melania Trump, London Mayor Sadiq Khan, U.K. Prime Minister Theresa May, and U.S. Vice President Mike Pence shared their sorrow on Twitter.

President Donald Trump tweeted that “flying water tankers” could possibly be used to put out the fire. The French security civil agency responded that that suggestion could result in the entire building’s collapse.

The Vatican issued a statement regarding the fire, stating that “The Holy See has learned with shock and sadness the news of the terrible fire that has devastated the Cathedral of Notre Dame de Paris, symbol of Christianity, in France and in the world. We express our closeness to the French Catholic and to the people of Paris. We pray for the firefighters and for all those who are doing everything possible to face this dramatic situation.”