When the Notre Dame cathedral caught fire in April 2019, Paris came very close to losing over 800 years of history. Now engineers are in a different race against time: to rebuild the roof and secure the medieval structure. Underneath the charred scaffolding and vaulted ceilings of the cathedral, scientists study the components of Notre Dames iconic structure to puzzle out how best to repair it. Producer: Alessandra Bonomolo, Laurie Cahalane, Melanie Wall. Narrator: Eric Meyers.