One of the world's most renowned Catholic cathedrals, Notre-Dame in Paris, suffered massive damage after a fire tore through the 12-century-old structure in April, destroying its roof and causing its spire to collapse.

Now a vulnerable structure, it is estimated that it could cost anywhere from $1.13 billion to $2.3 billion to repair the historic landmark.

So far, $800 million has been pledged in reconstruction funds and the French army general in charge of rebuilding the cathedral says renovation work will begin later in 2020.

NOTRE-DAME CATHEDRAL CAN'T CELEBRATE CHRISTMAS MASS FOR FIRST TIME IN 200 YEARS FOLLOWING DEVASTATING FIRE

Gen. Jean-Louis Georgelin told a French parliament commission on Jan. 22 that workers were still securing the structure, which had 50,000 tubes of scaffolding crisscrossed along the back as ongoing renovations were already taking place when the fire broke out on April 15, 2019.

Removing those scaffolding without further destabilizing the structure is one of the toughest parts of the cleanup but specialists plan on doing so by mid-February.

The roof, which toppled in flames, threatened the stability of the massive stone structure and made the surviving vaults within particularly vulnerable to damage.

Monsignor Patrick Chauvet told The Associated Press in December that "there is maybe a 50 percent chance it will be saved. There is also a 50 percent chance of scaffolding falling onto the three vaults, so as you can see the building is still very fragile.”

The entire removal process for pre-existing construction elements will take four months and involve professional climbers removing 40,000 pieces of scaffolding weighing a total of 200 tons, Georgelin said.

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Further complicating the project: the 460 tons of lead contained on the cathedral's roof and spire, which blew through the city of Paris as the structure burned under the blaze. Notre-Dame must be completely cleared of the lead and decontaminated before experts are able to make decisions about how to start rebuilding the medieval landmark.

President Emmanuel Macron has vowed to rebuild the historic tourist attraction by 2024, the year that Paris will host the Summer Olympics, but some experts said it could take another three years before the cathedral is safe enough for people to re-enter.