The wall is part of a larger movement inspired by the "John Lennon Wall" in Prague where people post Beatles lyrics and notes supporting global causes.
RELATED: Riot police clash with protesters at Hong Kong airport
In the Bay Area, there was one in San Francisco's Chinatown earlier in the summer. And there's currently one at UC Berkeley-- which has led to clashes among students.
Many students from mainland China want the wall taken down. Some are adding their own messages.
"The only thing I want to write is 'I love China,'" Tiahui Xie, a summer session student at Cal who is visiting from China, told ABC7.
“John Lennon” walls - where ppl write notes of support for Hong Kong - have popped up around the world. This one is at @UCBerkeley.— Liz Kreutz (@ABCLiz) August 13, 2019
Some students from mainland China have been tearing the notes down. You can see the difference from today vs yesterday (last 2 pics from a student) pic.twitter.com/sPWoTtiLvA
The wall, which asks people to leave notes of support for the Hong Kong protesters on sticky notes, was put up in June by activists in the Bay Area.
One of the Cal students who is behind the wall, and believes the Chinese government is encroaching on Hong Kong's autonomy, says everyday students tear down the posts and she goes back and puts the notes back up.
"Why I'm here is to let the international world know and raise awareness for people who don't know what's happening in Hong Kong." The student, who wears a mask and asked to remain anonymous out of fear of retribution by the Chinese government said, "And let them know what is the case of the police brutality happening in Hong Kong."
As she was posting new flyers criticizing the Chinese government on Tuesday afternoon, a swam of Chinese students confronted her saying they disagree.
"Hong Kong is a part of China, it's absolutely true," Xiu Ming Hung, a Cal student from China, said. "And these people they use violence to beat the Hong Kong police."
The student who supports the wall believes it's the other way around.
"People are so angry and eager to keep going," she said, "Because the government doesn't care what our demands are and they just like closing their ears."
On Tuesday, thousands of pro-democracy protesters in Hong Kong swarmed the Hong Kong International airport causing flights to be canceled for a second straight day.
Flights to Hong Kong out of San Francisco International Airport were not canceled, but it did impact people trying to go get home.
Brenaia Roberson's 16-year-old son got stuck in Hong Kong with his basketball team from Oakland after their flight Monday was canceled.
"I was pretty nervous because I wasn't aware of the conflict, what's going on, so I was pretty nervous about everything," Roberson said. "This was his first international trip. 16-years-old-- but I'm happy to say he is on his way back."
Roberson says nearly 20 students from the Bay Area were in China with the TKB basketball team. The teenagers were able to get on a later flight that arrived on Tuesday.
On Saturday, the Northern California Hong Kong Club has planned a protest in support of the Hong Kong demonstrators. It is scheduled for 2 pm at the Embarcadero Plaza.