Catholics around the world watched in disbelief as the iconic Notre Dame Cathedral burns in Paris. The fire sparked April 15, 2019, around 6:30 p.m. local time and raged for hours.

One of the items inside the cathedral that onlookers worried about was the historic organ. Officials confirmed to the Associated Press that the instrument appears to have survived the devastation. But the level of damage, due to the intense heat inside the cathedral, needed to be evaluated. Organ builder Bertrand Cattiaux told the New York Times that damaged portions of the organ appeared restorable and that none of the pipes had collapsed.

The exact cause of the fire remained unclear hours after the fire had been doused, but early reports suggested that renovation work may have been a factor. The fire began in the cathedral’s attic and appears to have been an accident; officials have said there is no evidence of arson. The nearly 300-foot tall spire at the top of the cathedral collapsed and a majority of the roof caved in. Officials say the towers are safe and responders managed to recover priceless relics such as the crown of thorns and religious artwork.

Hundreds of firefighters struggled to get the flames under control, as smoke billowed high into the air over the city. Officials explained that they could not use aircraft to dump water over the top of the building because doing so could have caused the entire structure to collapse. One firefighter and two police officers sustained injuries, the fire department shared on social media.

The current organ at Notre Dame dates back to the 18th century. François Thierry is credited with reconstructing the massive instrument in the 1730s. He reportedly kept at least 12 pipes that had been installed in the 14th century.

Then in the 1860s, Aristide Cavaille-Coll doubled the number of pipes. The modified instrument was dedicated in 1868.

It is the largest organ in France. The Guardian reports that it has five keyboards, 109 stops and approximately 8,000 pipes.

The organ system underwent a major renovation in the early 1990s that lasted nearly three years. The project cost more than $2 million as the instrument was installed with more modern technology.

According to the Christian Science Monitor, computers were linked to the pipes and foot pedals, “as well as to a musical-instrument digital interface (MIDI) that records and allows for instant replay, a voice synthesizer, a printer, and a telephone line to an office near Versailles.” The upgrades allowed musicians to compose new music and record it while sitting at the keyboard.

Rare glimpse of Notre Dame's organAP Television Paris – 2 May 2013 1. Wide exterior shot of Notre-Dame Cathedral 2. Mid of Philippe Lefebvre, Notre-Dame Cathedral organist, taking seat at organ 3. Various of Lefebvre's playing "Piece Heroique" composed by Cesar Franck 4. Wide of organ pipes 5. Mid of organ pipes and wooden structure 6. Wide of visitors listening… 2015-07-31T11:03:05.000Z

The Associated Press spoke with Notre Dame Cathedral organist Philippe Lefebvre in 2015. Translated from French, he explained that the organ’s age is a major reason why the sound is so fantastic. He told the AP, “Notre Dame is different because it is one of the only organs that has kept the traces of the centuries. As has the cathedral itself. So we have some tones from before the Revolution, some from the 19th century similar to ones of a symphonic orchestra and also all the recent inputs from the 20th century. So we have three or four authentic centuries of music.”

Lefebvre said he first heard the organ inside Notre Dame as a teenager and was hooked on it. “Here in Notre Dame when you play a tone, the acoustics make the resonance last for eight to nine seconds. It is exceptional, the sound spreads across the whole structure and you feel it when you play, the sounds come back at you. It doesn’t just stop immediately. It provokes sensations for the organist.”

Construction of the Notre Dame Cathedral began in 1163 under the order of the Bishop of France at the time, Maurice de Sully. It took nearly two centuries to complete; the cathedral was consecrated in 1345.

People around the world shared their grief on social media and mourned the presumed loss of the iconic instrument and cathedral.

I went with my sister a few years ago. I distinctly remember the notes of the organ echoing off the interior walls, and I felt so safe while I sat in the pews, marveling at the Notre Dame’s beauty. I can’t tell you how much I’ve cried seeing it ablaze. https://t.co/hsBG4k05Sf — Kelsey Mo (@kelseymo_news) April 15, 2019

Notre Dame is the most magical place I’ve ever been. Everyone knows about the windows, but the really beautiful things are inside: The organ, the statue of Joan of Arc, the reliquary holding the crown of thorns. I hope some of it was saved. pic.twitter.com/BrD5TBd4GY — Sarah Walsh (@sarahbellewalsh) April 15, 2019

The Notre Dame organ is one of my favorites. I treasure it. I here is a video of the organ on Palm Sunday in 2017. pic.twitter.com/uhZ8tL7UKx — Sydney O'Dear (@sydneyodear) April 15, 2019

I attended an organ concert in Notre Dame Cathedral last month. Who would ever know that this view would be gone forever? So sad to see this loss of architecture and history and beauty. pic.twitter.com/wd6YE6FhgN — Lois Patterson (@loisrp) April 15, 2019

Notre Dame: heard the pipe organ there once. The resonance of the sound shook the stone, and was so overwhelming and penetrating as it filled that vaulting soaring space that for the barest of moments I thought I could actually see the angels flying around. ?#NotreDame #vss365 — C. R. Norris (@CRNorris2) April 15, 2019

Remembering the grandeur of #NotreDame — the reverberations of centuries-old organ music throughout the cathedral, especially, and the way sunlight slants through stained glass windows, painting rainbows on marble pillars. pic.twitter.com/sSXf3e6F2D — Melodye Shore (@MelodyeShore) April 15, 2019

J.S. Bach : Toccata and fuga in d minor at Notre Dame de Paris (Best Ver… https://t.co/r4sYSZkLcu via @YouTube in Memory of one of the best Cathedral organs I’ve ever heard, and one of the best pieces of organ music . — Steve Foster Not EU I’m UK xmil (@stevenfoster4) April 15, 2019

Notre Dame – I fear for the glorious organ. The thought of all that potential music melting inside like tears of metal. — Michael Bywater (@mbywater) April 15, 2019

I was left in awe walking through Notre Dame on a Sunday, the organ playing, the people worshiping, the bells chiming. It hurts seeing the cathedral up in flames. — Ryan Martin (@RyMartin24) April 15, 2019