Twenty years ago the doors to University Hall were open, and the students were inside.

Yesterday the doors were locked, but the activists of 1989 joined the activists of 1969 in a rally to remember the takeover of the building 20 years ago which protested the presence of the Reserve Officer Training Corps (ROTC) on the Harvard campus and the University's expansion in Cambridge.

About 500 people attended the noontime rally outside University Hall, including many participants in the 1969 takeover and student strike who returned to Harvard for a weekend of activities commemorating the protests of that spring.

"We're here to celebrate how we can succeed in changing this institution, and if we can succeed in changing this institution, we can change the world," said Mary E. Summers '70, a 1969 protestor who was the main speaker.

Summers, a doctoral candidate at Yale, served as Rev. Jesse L. Jackson's chief speechwriter in his 1984 presidential campaign.

In April 1969, several hundred students occupied University Hall for almost two days before then-President Nathan M. Pusey '28 sent in 400 police officers to evict them forcibly. A three-day student strike followed the bust, and the turmoil led to faculty acceptance of the protester's demands, which included the abolition of ROTC on campus and the creation of an Afro-American Studies Department.

"We won on every one of those demands," said Dale E. Fink '71-'72. "We're here to commemorate those victories and to affirm...those events are still meaningful for us and those are the values we still live by...We did not come here for nostalgia."

Summers said the protesters of 1969 changed Harvard. "For those few weeks...we had taken this university away from the elite, and we turned it into a real school. We were showing people in this society they could change the institutions they were part of," she said.

"We are forging links between 1989 and 1969, links between people of different groups. Activism is rising again, and I think it needs to," said Aldyn McKean '70-'71, a self-proclaimed "faggot revolutionary," who is currently a gay rights activist.

Representatives from activist organizations joined in the rally, including speakers from the Bisexual, Gay and Lesbian Students Association (BGLSA), the Harvard Union of Clerical and Technical Workers (HUCTW), the Minority Student Alliance (MSA) and other campus groups.

Students from the Divinity School Peace Committee, whose members took sanctuary in Memorial Church yesterday morning to protest Harvard's investments in South Africa, also participated.

Speaking of Harvard student activism now, John Donaghy '90 from the Committee on Central America (COCA) prompted applause when he said, "We need to be much more militant to get activism. The administrators don't care."

"We should be making sure that the racism and sexism here should not be tolerated. We have a chance to bring social responsibilities to Harvard by electing Bishop [Desmond M.] Tutu [to the Board of Overseers]," said Domenic M. Bozzotto, who heads Local 26, the Harvard dining hall workers' union.

The Radical Arms Troop, a singing group of six students who took part in the 1969 protests, drew cheers from the vocal audience for such lyrics as "ROTC, keeping all the people in slavery," and "It's the same bosses here as in Pretoria...Listen, Derek Bok, divest your racist stock."

The beginning of the rally offered more disruption than organizers expected, as a man carrying a sign that said "Fight and Destroy Jewish Zionist Conspiracy Today. Tomorrow may be too late," was pushed down the steps of University Hall where speakers were to stand.