Paris -- After a fire that raged for at least 12 hours, Notre Dame Cathedral stood damaged but defiant Wednesday and the cross on the church's altar, though buried in debris, was almost shining, reports CBS News' Roxana Saberi.

Almost $1 billion has been raised to rebuild the iconic monument, the Associated Press reported, and French Prime Minister Edouard Philippe announced an international competition for architects to rebuild the spire, according to the French news agency AFP.

Local newspaper Le Parisian reported that a fire alarm went off late Monday, but that a computer glitch indicated the flames were in a different location. The paper said the fire may have begun at the bottom of the spire and been caused by an electrical problem in the elevator.

Construction workers brought in a delivery of wooden planks and a large crane Wednesday morning as crews inspected the damage and worked to make sure that what had survived the fire was structurally sound.

Inside, church pews were still in place, Saberi reports. Artifacts that could be rescued had been taken to Paris City Hall.

"Paintings, chairs, objects and candle holders, it was absolutely extraordinary because it's a miracle what was saved here," Christophe Girard, Paris' deputy mayor, told CBS News.

French President Emmanuel Macron hailed as heroes the brave firefighters who risked their lives to salvage what cultural treasures they could. Late Tuesday, he vowed to rebuild the eight-centuries old cathedral within five years.

"It's heart-wrenching," architectural historian Tricia Meehan remarked to CBS News, but she said reconstruction could take decades.

"It would take a really long time because we're talking about hand labor," she said.

Experts told CBS News it could take 40 years to rebuild the cathedral using medieval methods and materials.

Regardless of the time frame, however, Saberi reports that people on the streets of Paris were praying that Notre Dame would rise again.