Ten years after a mentally ill student fatally shot 32 people at Virginia Tech, survivors and families of the slain are returning to campus to honor the lives that were lost that day.

Virginia Polytechnic Institute and State University, widely known as Virginia Tech, is holding a series of events Sunday to mark the anniversary of the deadly campus shooting on April 16, 2007. Virginia Gov. Terry McAuliffe and U.S. Sen. Tim Kaine will be among the 10,000 to 20,000 people expected at the Blacksburg campus for the solemn occasion.

Kaine, who was governor at the time of the shooting, said he still vividly remembers the horrors of that day, but has also grown close to many of the survivors and the victims’ families.

“We’re going with a lot of different emotions, but we wouldn’t be anywhere else,” said Kaine, who is attending the service with his wife, Anne Holton.

The shooting at Virginia Tech was, at the time, the deadliest mass shooting in recent U.S. history. A massacre that claimed 49 lives at an Orlando, Florida nightclub surpassed it last year. It forced schools across the country to rethink campus security and reignited the debate over gun control that rages to this day.

On Sunday morning, McAuliffe and his daughter participated in a wreath-laying ceremony at 9:43 a.m. — the time when Seung-Hui Cho’s rampage in Norris Hall began.

The Roanoke Times reports that the pair, along with former Virginia Tech President Charles Steger and current President Timothy Sands and his wife, walked around the memorial, stopping at every one of the 32 stones arranged in a semi-circle, each engraved with the name of a victim.

“Our thoughts and prayers are with the families, survivors and the entire Virginia Tech community who have shown incredible strength and resilience while facing unimaginable grief,” McAuliffe said. “We should reflect on the heartbreaking events that took place and use this moment to come together to ensure an incident of this magnitude never happens again in our commonwealth.”

In a speech Sunday afternoon, Kaine said April 16, 2007 remains “the worst day of my life.”

Kaine had been governor for a year and a half when the shooting occurred, and said since that day, he’s kept in touch with many families who lost children, spouses or loved ones in the mass shooting.

Kaine recalled speaking with families as he was leaving the governor’s mansion in 2010.

“I remember saying to them, I’ll never understand what you lost, because I never lost a child, a spouse, a parent or a sibling,” he said. “But as somebody who has grown to know the biographies and stories of each of these 32, I begin to have a sense of what the commonwealth lost, what the country lost, what the world lost on April 16, 2007.”

After Kaine’s remarks, short biographies of each of the victims were read aloud.

On Sunday evening, students, faculty and visitors will gather for a candlelight vigil.

At 11:59 p.m., a candle at the April 16 memorial that was lit at midnight will be extinguished and carried into Burruss Hall. The events were planned by current students over the last 18 months, said Mark Owczarski, a Virginia Tech spokesman.

Leading up the anniversary, the atmosphere on campus has been one of reflection and remembrance, Owczarski said. Most of the current students were in elementary school when the shooting occurred, but understand that the “tragedy is part of Virginia Tech,” he said. Counselors have been stationed at commemoration events throughout the weekend to provide support.

“It is together — as a community — that we endure difficult times,” Tech President Tim Sands said in a recent email to students and staff.