ROUGH CUT (NO REPORTER NARRATION) A week-long series of events commemorating the 20th anniversary of the Columbine High School massacre culminated on Saturday with a remembrance ceremony celebrating the lives of the 13 victims slain in the rampage.

Survivors and people who lost loved ones from the tragedy spoke at Saturday's service in Littleton, Colorado.

On April 20, 1999, two Columbine students, just three weeks shy of graduation, stormed the suburban Denver school armed with shotguns and semiautomatic weapons, fatally shooting 12 students and a teacher before committing suicide.

For the relatives of those they killed, April 20 evokes a mix of emotions from sorrow and anguish to fond memories of loved ones.

Betty Shoels, the aunt of murdered student Isaiah Shoels, said her 18-year-old nephew was a fun-loving athlete who was always smiling, despite feeling out of place as one of the school's few African-American students.

"What I miss most is his laugh," Shoels told Reuters.

"He was just a great kid who loved to joke." This year's remembrances were marred this week when a Florida teenager, who authorities said was "obsessed" with Columbine, traveled to Colorado where she died of an apparent self-inflicted gunshot.