But despite the tremendous loss, the fire has given experts an exceptionally rare opportunity to investigate parts of the cathedral’s structure that were previously unreachable, revealing forgotten burials and providing insights into the working methods of medieval artisans.

“The worksite enabled us to collect an enormous and unprecedented amount of data on the materials used in the construction of the cathedral's masonry, and on the way in which these materials were worked and put up together,” says Yves Gallet, a professor of the history of medieval art at Bordeaux-Montaigne University, who leads the working group studying the cathedral’s masonry. 

“In order to do this, we had to be able to examine the walls, pillars and vaults very closely—which we were able to do from the scaffolding, with unrivalled precision in observing and recording the data, and with the possibility of taking samples from places that had not previously been accessible.”