PARIS — With just days to go until the opening ceremony of the Olympic Games in Paris, many people may be casting their minds back to more than five years ago, when the city’s treasured Notre-Dame Cathedral was engulfed in flames. …Parisians themselves flocked in person to see their more than 800-year-old church burning. Many watched in horror as the iconic spire collapsed, and the wooden roof fell in. To this day, there is no clear answer as to what caused the fire. …The rebuilding and restoration won’t be ready quite in time for the Olympics, but it’s scheduled to reopen to the public on Dec. 8. …The tools used to rebuild the roof span the ages, from modern welding apparatuses to axes forged using medieval techniques, including some from Montreal. …The 2019 fire caused the complete destruction of Notre-Dame’s wooden roof. To rebuild, experts searched forests throughout France for thousands of perfect oak trees.