The iconic Notre Dame cathedral in Paris is in flames. Photos and video posted on social media show huge plumes of grey smoke filling the sky, and flames raging along the base of the medieval church's spire, which is undergoing renovation. The spire is gone -- collapsed.The fire has sent ash pouring onto Parisians and tourists who are looking on in shock from the streets below. The 12th century cathedral is among the most visited landmarks in the world. French media quote the Paris fire brigade as saying the fire is potentially linked to the renovation work. (The Canadian Press)