London, April 17 -- Notre Dame in Paris is not the first great cathedral to suffer a devastating fire, and it probably won't be the last.

In a sense, that is good news. A global army of experts and craftspeople can be called on for the long, complex process of restoring the gutted landmark.

The work will face substantial challenges - starting immediately, with the urgent need to protect the inside of the 850-year-old cathedral from the elements, after its timber-beamed roof was consumed by flames .

The first priority is to put up a temporary metal or plastic roof to stop rain from getting in. Then, engineers and architects will begin to assess the damage.

Fortunately, Notre Dame is a thoroughly documented building. Over the years, his...