They sang the Belgian national anthem together and then a moment of silence for the victims of the terror attacks.
"It shows how united our country is, and important in times like this," said Harold DeBlander, who is from Brussels.
DeBlander is a member of the Belgium Club of Northern California. He says there are approximately 1,000 members and many have loved ones in and around Brussels.
On Friday, the main fugitive in November's Paris terror attacks was arrested in Belgium. Deblander says that's less than a mile from where his sister lives.
"I knew Belgium was going to be next. I was surprised it didn't happen sooner," he said.
PHOTOS: Dozens killed in terror attacks in Brussels
"We're a good people. The question is - why? Why us?" asked John Vanloo.
Jean-Loick Michaux has been texting friends and family back home. He says the attacks will not break his country.
"They are trying to divide us, but in the end, we are all one humanity," said Michaux.
Liesbeth Dewaele worked at Brussels International Airport and still has good friends there.
"Unfortunately, one colleague was badly injured, but he will survive," she said.
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"My heart is with all the people in Belgium, my family and friends, but also my Belgium friends here in the Bay Area. I have not heard from everybody, and I'm sure they may have some people affected," said Leslie DeSaeyere, also a Belgium native.
"It's very difficult to be far away from your family at this time," she said.
Outside SF City Hall right now - support for Brussels pic.twitter.com/w63eTZZXPU— Melanie Woodrow (@MelanieWoodrow) March 23, 2016
Growing tribute. Vigil here at 730pm pic.twitter.com/Ba75a5KUQx— Melanie Woodrow (@MelanieWoodrow) March 23, 2016