I don't want to believe it's true. What a tragedy for one of the most elegant and iconic structures built by humans. Its cornerstone was laid in 1163, and it opened in 1345. Generations have been awed by it.
The spire has fallen and firefighters are racing to fight back the flames before the bells fall.
Cause as yet unknown.
Latest CNN update (approx 23:10 Paris time) is that the fire is cooling, the main towers are not in danger, and current efforts are to move some of the priceless art to safety. Much of the artwork had already been removed due to construction on the spire.