According to architectural historians, the cathedral's medieval stone vaults — which served as a buffer for the fire after it burned through the wooden roof — had a hand in this.
Dr Robert Bork, an architectural historian at the University of Iowa, told the ABC the cathedral boasts some of
the earliest six-part vaults used in the 12th century.
Innovation and exploration in the Middle Ages resulted in the creation of wider vaults that would better allow for elaborate windows than previous Romanesque churches, he explained.
"When the spire crashed through [the cathedral], that was a problem obviously and in some places the fire got through, but most of the vaults seem to have survived, which is a testament to how well they were put together in the 12th century."
The general principle of a vault, Dr Bork explained, is the same as that behind an arch, which sees lots of stones that are relatively small work to span a large space.
"So, in Notre Dame, [these stones] cross the span which is about 14 metres across on the inside, and they're all essentially wedged together so that when gravity pulls down on each of those little stones, [the structure] is held into place by the friction of its neighbours in a kind of wedging action."
How a medieval design trick helped save Notre Dame from perishing completely