AMSTERDAM (KABC) --The downing of Malaysia Airlines Flight 17 claimed victims from 11 countries and all walks of life.
Families have been gathering at Amsterdam's Schiphol Airport where their loved ones boarded Flight 17. Others gathered across the world in Kuala Lumpur, where it was supposed to land.
The plane was carrying 283 passengers and 15 crew members. They included vacationers, a nun and teacher from Sydney, a Dutch senator, a World Health Organization spokesman, students and a large contingent of scientists heading to Melbourne, Australia for the 20th International Aids Conference. Among them, Joep Lange, a world-renowned AIDS researcher and former president of the International AIDS Society.
"Joep was a man who knew no barriers," the Academic Medical Center hospital in Amsterdam said. "He was a great inspiration for everybody who wanted to do something about the AIDS tragedy in Africa and Asia."
Dutch AIDS activist Pim de Kuijer, once a political intern of former Dutch lawmaker Lousewies van der Laan, was also killed.
The World Health Organization says their spokesman, Glenn Thomas, a 49-year-old Briton, was also killed on his way to the AIDS conference.
Thomas "will be remembered for his ready laugh and his passion for public health," said Gregory Hartl, another spokesman for the U.N. health agency.
A memorial was held Friday afternoon at the AIDS Healthcare Foundation in Hollywood honoring the many researchers who dedicated their lives to curing AIDS.
"We felt it was important to honor the memory of the more than 100 AIDS advocates who perished," Michael Weinstein of the AIDS Healthcare Foundation said.
At least one American was killed, President Barack Obama said Friday. The American victim was identified as Quinn Lucas Schansman, 19, a male U.S.-Dutch citizen.
One of the passengers attended college in the United States. Indiana University said Friday that one of its students, 25-year-old Karlijn Keijzer, a native of Netherlands, was among the passengers on the plane. She was going on vacation with her boyfriend.
"I'm just in disbelief and expecting Karlijn to pop up on Facebook and tell everybody she's OK," Keijzer's roommate, Rachel Weigler said.
The dead included a Dutch senator, Willem Witteveen of the Labor Party, the Senate announced.
Students at the Kincoppal-Rose Bay School of the Sacred Heart in Sydney gathered Friday for a special prayer meeting to remember Sister Philomene Tiernan, a 77-year-old teacher who was killed.
An Australian woman who lost a family member on the Malaysia Airlines plane that was shot down in eastern Ukraine also lost loved ones on the jetliner that vanished in March.
Kaylene Mann's brother Rod Burrows and sister-in-law Mary Burrows were on board Malaysia Airlines Flight 370 when it disappeared over the Indian Ocean.
On Friday, Mann found out that her stepdaughter, Maree Rizk, was among the 298 passengers on Flight 17, which U.S. intelligence authorities believe was shot down by a surface-to-air missile on Thursday.
"It's just brought everyone, everything back," said Greg Burrows, Mann's brother. "It's just ... ripped our guts again."
Dutch passenger Cor Pan and Neeltje Tol were on their way to a beach vacation in Bali, Indonesia. Family members tell ABC News that the couple had recently opened a flower shop in their Dutch hometown.
A handwritten note taped to the storefront above a bunch of orange roses, read: "Dear Cor and Neeltje. This is unwanted, unbelievable and unfair. Rest in peace. We will never forget you."
Pan posted an eerie message on his Facebook page just before take-off of what appears to be the doomed plane on a tarmac with the following caption: "Should it disappear, this is what it looks like," a reference to Flight 370.
The haunting images of the MH17 wreckage will not soon be shaken, especially from the minds of those who were supposed to be on the plane.
Juan Jovel was on his honeymoon. He and his wife made the decision to take a later flight to avoid being jet-lagged, a seemingly minor decision that was the difference between life and death.
"We're feeling lucky, but at the same time, our hearts bleed for these families that are expecting their loved ones to come home," said Jovel.
The Associated Press contributed to this report.