Kofi Annan, former secretary-general of the United Nations, returned to his alma mater in St. Paul on Monday and credited Macalester College for shaping him for a career in diplomacy.

"It all started here in 1959 when I was a student," Annan said. "The values and lessons I picked up here stayed with me throughout my life."

Annan, a member of the class of 1961, was on campus for the renaming of the Kofi Annan Institute for Global Citizenship in his honor. In a series of events on campus, the Ghanaian diplomat and Nobel Peace Prize winner met with his classmates, held a conversation about world affairs with the college president and told students they are never too young to be leaders.

"Today we have a lot of young people leading in the world, including those who want to end gun violence in this country," Annan said, referring to activism related to the recent mass shootings on school campuses across the United States.

St. Paul Mayor Melvin Carter introduced Annan before the unveiling and mentioned his memories of growing up in St. Paul when Annan was secretary-general of the U.N. — and an inspiration to him.

"I am excited to know what one graduate can do, I can't wait to see what a campus of current students can do," Carter said, joking that his staff needed to get a picture of him sitting next to Annan.

Macalester President Brian Rosenberg called Annan a role model.

"The measure of his achievements is not just the fact that he, with the U.N., won the Nobel Peace Prize, but it is by the number of people he helps and number of people he inspires," Rosenberg said.

Annan was last at Macalester in 2009 when a life-size bronze bust of him was unveiled. In 2006, he was an inaugural speaker at the then-new Institute for Global Citizenship. The institute now renamed for him "fosters global citizenship by advancing scholarship, reflection, and ethical action in our local, national, and international communities," according to the college website.

Thousands of students, faculty, alumni and others packed an auditorium at the campus fieldhouse to hear Annan's wide-ranging conversation with Rosenberg. The one-hour session began with a performance by Macalester's African Music Ensemble, and then Annan touched on topics from Syria and the refugee crisis to privacy and propaganda concerns on social media.

"No society can long prosper without respect for rule of law and human rights," he said about his experience working as a peace envoy in Syria.

He reflected on the struggle in Syria, saying, "A peacemaker cannot want peace more than the people who gave him the job. In war, all are losers, including those who claim to be victorious."

In the middle of serious discussions, there were lighter moments, too. The audience broke out laughing when Annan said he and fellows students in the Ambassadors for Friendship Program once volunteered to go to prison as part of their effort to get to know the United States.

"There are not many people who want to go inside a lockup," said Annan, who studied economics.

Rosenberg asked what Annan does for fun. "I and my wife watch football and applaud together," he said.

For students like Anni Clark, it was exciting to listen to Annan up close.

"We had heard of him but never thought we would listen to him in person," said Clark, a freshman studying international relations and linguistics, who was among the first people to enter the auditorium.

It was also special occasion for alumni, who got to listen to Annan and see each other after a long time.

"Given his personality, we always thought he would be president of Ghana one day," said Dean Edstrom, who went to Macalester with Annan and graduated in 1962.

The day ended with a musical surprise for Annan when the audience stood and sang "Happy Birthday" to him. Annan turned 80 in April.

"This is the biggest number of people I have seen wishing someone happy birthday," Annan said. "You probably need to be 80 to get this."