SAN FRANCISCO (KTVU/BCN) - Grace Cathedral had a huge turnout Monday night for a solidarity concert with the people of France.
San Francisco and Paris are sister cities.
Grace Cathedral and the Notre Dame de Paris are sister cathedrals, and about 60,000 people of French heritage live in the Bay Area.
"Every organ is different and every acoustic is different," organist Johann Vexo told KTVU, as he prepared to perform for an overflow crowd up to 5,000 people.
Vexo was one of five organists at Notre Dame and was playing at a mass inside when the devastating fire broke out.
"I was in the cathedral, but I didn't see any fire, any smoke and didn't smell anything," said Vexo, of the early moments of the evacuation.
In the two weeks since the fire, historic cathedrals in New York and Washington, D.C. have also held concerts to show support.
With its French Gothic architecture, Grace Cathedral is in many ways a replica of Notre Dame.
"Our communities can count on each other in times of need," San Francisco Mayor London Breed told the crowd, recalling how impressed she was to see Parisians gathering and singing hymns as their beloved landmark burned.
"That spirit can never burn," continued Breed, "and San Francisco, like Paris, is a resilient city."
The mayor also spoke of Sri Lanka's deadly Easter bombings, fires at black churches in Louisiana, and the past weekend's synagogue attack in Poway, Calif.
The Notre Dame fire is suspected to be accidental.
"Well I wept when I saw it, " said Marc Andrus, Episcopal Bishop of California, who welcomed the crowd.
Bishop Andrus calls Notre Dame a global monument to faith, art, and common humanity:
"We need things that are beautiful and that uplift us, and it has been doing that for many, many, many, years, centuries."
The free concert came together swiftly, spurred by San Francisco's Symphony, the Opera and the American Bach Choir.
Some of the warmest applause came for famed mezzo-soprano Frederica Von Stade.
The cathedral itself has seating for 3,000 with more room standing, and overflow rooms below with an audio-video feed.
"There has been only a few times in history when Grace Cathedral has hosted close to 5,000," concert coordinator David Perry told KTVU.
"One of the most memorable was when Dr. Martin Luther King, Jr. spoke here, people were flowing out the doors." Dr. King preached at Grace in 1965.
Only once since then, has turnout rivaled that day, and that was a spontaneous gathering of thousands after the September 11, 2001 terror attacks on the United States.
Without invitation, people flocked to the cathedral to be together in grief and prayer.
So the outpouring for Notre Dame was stunning.
"Notre Dame is our lady, our maternal figure, our mother," said Emmanuel Lebrun-Damiens, Consulate General of France, thanking the audience for their support. Lebruns-Damiens told KTVU he finds Grace Cathedral comforting, with its rose windows and arches so akin to Notre Dame.
The distinctive spires on both cathedrals were almost identical. Now the Paris skyline has lost its spire.
"People who are old may be thinking they will never get to go again because it would take years to renovate," Lebrun-Damiens told KTVU, sharing his hopes for a rapid rebuild.
"For them, I think we need to do it fast because people still have things they need to tell her."
For Johann Vexo, the last musician to play at Notre Dame, the magnitude of the fire didn't hit untl he had arrived home after evacuation.
"A colleague called me from abroad and he was watching on social media, and saw something serious had happened at Notre Dame, so I immediately understood and looked out my window to see the smoke."
Vexo has been an organist at Notre Dame for 15 years.
"I miss it every day, " he told KTVU, "and I will miss it for a long time."