Watch: The moment Notre Dame Cathedral's spire fell, engulfed in flames

The Notre Dame Cathedral in Paris was engulfed in flames on Monday, police said, causing untold damage to the 856-year-old building.

"Notre Dame Fire in progress," police said on Twitter. "Avoid the area and facilitate the passage of emergency vehicles and intervention of the @prefpolice."

Patrick Galey, a correspondent for the AFP News Agency, tweeted a video of the cathedral's spire falling amid giant flames.

Watch the video below.