April 18 (UPI) -- France on Thursday began a daylong tribute to honor hundreds of firefighters who fought for hours to extinguish the fire at the historic Notre Dame Cathedral this week.
French President Emmanuel Macron led the tribute to the 400 firefighters who battled the flames and rescued some of the cathedral's most valued treasures. Ceremonies were held at the Elysee presidential palace and Hotel de Ville. An event at Paris City Hall included a violin concert and readings from Victor Hugo's The Hunchback of Notre Dame.
The firefighters have been praised for working quickly to save the 850-year-old cathedral. Without their rapid response the entire building could have burned to the ground in a "chain-reaction collapse," said Jose Vaz de Matos, a fire expert with France's Culture Ministry.
Firefighters wearing full bunker gear climbed up a narrow, spiral staircase to the top of one of Notre Dame's famed towers. It took nine hours to put the fire out.
"We knew that the roof was burning, but we didn't really know the intensity," said firefighter Myriam Chudzinski, one of the first to reach the top. "It was from upstairs that you understood that it was really dramatic. It was very hot and we had to retreat, retreat. It was spreading quickly."
Investigators said the first sign of trouble came just after 6 p.m. Monday when an alarm showed a false location for a fire. Another alarm sounded minutes later, by which time the fire had spread across the roof and engulfed the spire within an hour. The false initial alarm was blamed on a software bug.
A team of 50 investigators are questioning church employees and construction workers. Officials said 40 people have been interviewed so far, some more than once. Experts said the church structure itself is still fragile and more statues are being removed in case they collapse.
Macron said he wants to rebuild the cathedral in five years, but some experts have said it could take as many as 15 years. Donations for the effort so far total more than $1 billion. French officials are asking architects worldwide to submit designs for rebuilding the spire.