Photos: Much of Notre Dame Cathedral's structure and artifacts miraculously survive the destructive fire

A cross situated in front of the altar, along with much of the historic Notre Dame Cathedral's interior, survived Monday's fire in Paris, France.

Photos snapped from inside the 850-year-old Gothic church show smoke and fire billowing inside the nave of the church. Rows of wooden pews leading to the altar also appeared intact.

"The altar and its cross are preserved. It's not as bad as I feared," Mayor Anne Hidalgo told Le Monde, according to the New York Post.

Flames and smoke surround the altar and cross during the fire at Notre Dame Cathedral. Philippe Wojazer/AFP/Getty Images

Here's what the altar looked like after firefighters extinguished the fire:

Debris from the fire is seen throughout the central part of the cathedral.Christophe Petit Tesson/AFP/Getty Images

A close-up of the altar and damage surrounding it and the cross. Ludovic Marin/AFP/Getty Images

The Rose windows, a trio of stained glass windows dating back to the 13th century, survived, according to the Archbishop of Paris, CNN reported. The windows are featured in the photo below:

The Rose Windows appear in the background of this image taken after the fire.Ludovic Marin/AFP/Getty Images

A broader view of the devastating damage can be seen in this photo:

The aftermath caused by the huge fire. AFP/Getty Images

On Tuesday, officials worked to assess the damage.

Officials begin assessing the damage inside the cathedral.Christophe Petit Tesson/AFP/Getty Images

Watch:

Watch Paris firefighters surveying the damage.

Treasures, Relics Rescued From Notre Dame Cathedral Fire | NBC Newsyoutu.be

On Monday, firefighters swarmed the historic cathedral that houses numerous Christian artifacts and treasures.

Flames rise from the roof of the Notre Dame Cathedral. Michel Stoupak/NurPhoto via Getty Images

Daylight shines through the hole caused when the roof collapsed. Christophe Morin/Bloomberg via Getty Images

The facade and twin bell towers were constructed in the mid-1200s. The towers were the tallest structures in Paris until the Eiffel Tower was erected in the late 19th century.

"[W]e can consider that the main structure of Notre-Dame has been saved and preserved," Paris Fore Brigade Jean-Claude Gallet told Agence France-Presse.

The facade of the Notre Dame Cathedral one day after a swept through it.Chesnot/Getty Images

While the extent of the damage caused by water that was used to save the cathedral is still not clear, the main structure of the centuries-old building was saved.

Officials inspect the Notre Dame Cathedral. Lionel Bonaventure/AFP/Getty Images)

Firefighters worked for more than nine hours putting out the flames.

What other artifacts were saved?

The Crown of Thorns, believed by some to have been worn by Jesus when he was nailed to the cross and considered as cathedral's "most precious and most venerated relic," was rescued from the fire, according to Hidalgo.

The Crown of Thorns which is among the Notre Dame Cathedral's most treasured relics was rescued from the fire. Godong/Universal Images Group via Getty Images

Also rescued was the Tunic of Saint Louis:

The Tunic of Saint Louis was rescued from the massive fire. Patrick Kovarik/AFP/Getty Images

The Crown of Thorns and the Tunic of Saint Louis are safe at Paris City Hall, Franck Riester, France's culture minister, said Tuesday morning on French radio, the New York Times reported.

Just days earlier, 16 bronze statues were removed from the cathedral's roof and placed into storage as the structure was undergoing a massive restoration.

More than a dozen bronze statues sat safely in storage while fire ravaged the cathedral.Georges Gobet/AFP/Getty Images

The move saved the statues from destruction when cathedral's spire collapsed.

What else?

It's sill unclear whether or not a piece of the True Cross and one of the Holy Nails have survived.

Much of the cathedral's Great Organ, which dates back to the 19th century and contains more than 8,000 pipes from the 1200s appears to have survived.

A photo of the Great Organ taken in June 2018.Ludovic Marin/AFP/Getty Images

Organ builder Bertrand Cattiaux told the Times that there would be no guarantees until he visits the cathedral to asses the damage.

"We can just cross our fingers and wait," he said.