A picture taken on April 16, 2019 shows the altar surrounded by charred debris inside the Notre-Dame Cathedral in Paris in the aftermath of a fire that devastated the cathedral. - French investigators probing the devastating blaze at Notre-Dame Cathedral on April 15, 2019, questioned workers who were renovating the monument on April 16, as hundreds of millions of euros were pledged to restore the historic masterpiece. As firefighters put out the last smouldering embers, a host of French billionaires and companies stepped forward with offers of cash worth around 600 million euros ($680 million) to remake the iconic structure. (Photo by LUDOVIC MARIN / AFP)        (Photo credit should read LUDOVIC MARIN/AFP/Getty Images)