The entire wooden interior of the Notre Dame cathedral is feared destroyed

Andre Finot, a spokesman for Notre Dame, said there's a risk "nothing will remain" from the frame. The cathedral's wooden frame, which primarily consists of oak, contains beams that date as far back as the first frame built for the cathedral. That frame features trees cut down between 1160 and 1170, forming one of the oldest parts of the structure,

The prevailing Gothic style called for high vaulted ceilings. To accommodate this, the cathedral's plans required tall, sturdy oaks from a nearby forest.

Images from Notre Dame's website show the wood frame of the cathedral. Credit: From Notre Dame De Paris/Maurice de Sully association

To kick off the project, workers cleared 21 hectares of oak. Each beam of the intricate wooden cross-work was drawn from a different tree: estimated at 13,000 trees in total. To reach the heights the carpenters needed to build the structure, those trees would likely have been 300 or 400 years old, meaning they would have sprouted out of the ground in the eighth or ninth centuries.

This is what makes Notre Dame cathedral so iconic

The beams formed one of the oldest structures in Paris.

The dimensions of the framework are soaring: 100 meters long and 10 meters high. At the nave of the church, the frame is 13 meters wide, and at the transept it's 10 meters high, the church's website says.

Inside Westminster Abbey's $30M secret attic

During the Middle Ages, the carpenters first built the frame on the ground to get the dimensions and structure right. Then workers would have disassembled the frame, hoisting it up with lifting gear to the ceiling, where it would have been reassembled. Once in place, the beams extended toward the heavens at steep 55-degree angles.

Trees used to make the wood frame were likey 300 or 400 years old. Credit: From Notre Dame De Paris/Maurice de Sully association

Brazil: A museum is gone and might never return

But the wood that supported that lead roof is what burned.