Our hearts are breaking ...

Notre Dame Cathedral is burning. By-standers are screaming and crying, holding their heads in disbelief. It is perhaps the world's favorite monument -- the most-visited historic building in Paris. But beyond that, it is a world treasure -- not just a French monument -- but a relic for the entire world to enjoy and to share in the celebration of engineering, culture, art, religion. And it may be all but gone within the next few hours.

No cause has been released yet but the 12th-century cathedral was undergoing extensive renovations and was covered in scaffolding. Firefighters are battling now, but cinders are raining down on the street and the flames are far from under control.

Stay tuned for updates on this tragic story ...