The yellow-and-red-striped South Vietnamese flag flew alongside the U.S. and Massachusetts flags on Boston’s City Hall Plaza Tuesday to commemorate April 30, known as “Black April” to the Vietnamese diaspora.

Members of Massachusetts’ Vietnamese American community gather on City Hall Plaza each year to remember the fall of Saigon, the former capital of South Vietnam, in 1975.

After more than 20 years of the tradition, this is the first time Boston City Hall has recognized the event, and it’s the first time the South Vietnamese flag was raised.

State Rep. Tram Nguyen, the first Vietnamese American woman elected in Massachusetts, told the crowd it is important to remember the sacrifices of earlier generations.

“We need to remember the cause of the diaspora, but also to remember the resilience of the community and all the sacrifices the earlier generations made so that younger generations have these opportunities to succeed,” Nguyen said.

Many of the dozens of attendees wore military uniforms.

Ông Vinnie Bảo Toàn Than, the president of the Vietnamese-American Community of Massachusetts, recalled how many people lost everything when the North Vietnamese People’s Army took control of South Vietnam in 1975. After the reunification, hundreds of thousands of South Vietnamese people were forced into re-education camps.

“It was a horrible situation that only people from those years remember,” Than said. “This day is something we commemorate to remind the younger generation what happened and why we are here.”

Those are the memories that Ngọc-Trân Vũ and Linh-Phương Vũ hope to preserve as co-founders of 1975: A Vietnamese Diaspora Commemoration. They are leading the charge on an oral history project to capture local first-hand accounts and reframe the predominant narrative about the war.

But the initiative’s main focus is the creation of a permanent art installation in Dorchester’s Town Field Park. They’re fundraising for the initiative now and hope to have the installation in place before the 50th anniversary next year.

Ngọc-Trân Vũ’s father served in the South Vietnamese military during the war.

“It is so important to be able to honor and remember not only my dad but people who were part of the war and thinking about the impact and the legacy of the war and continue to remember that for the present and future generations,” Ngọc-Trân Vũ said. “To create a permanent marker for our own Vietnamese diaspora community.”

Following the commemoration, the group at City Hall Plaza traveled to the Vietnam Veterans Memorial along Morrissey Boulevard at UMass Boston to lay wreaths. None of the South Vietnamese people who fought alongside American soldiers are honored there.