The 71-year-old Ali is battling Parkinson's disease. But he can still draw a crowd and awe. During a musical presentation, the crowd of about 700 watched photos on a large screen that showed Ali with world and religious leaders and children. Another showed him holding the torch at the opening of the 1996 Olympics in Atlanta.
"I have so much admiration and so much respect and love for someone who truly has been a fighter in so many different ways," said Aguilera, who received the Muhammad Ali Humanitarian of the Year Award.
Aguilera was recognized for her role as an anti-hunger ambassador for the United Nations World Food Programme. She also has been a global advocate for fast-food company Yum Brands Inc.'s World Hunger Relief campaign to raise awareness and money to end hunger.
"From my heart, it really means a lot to be recognized for what's most important to me, and that truly is to connect with people on a universal level and use my voice to try and help inspire others to then use theirs," she said after receiving her award.
Carter, the nation's 39th president and a Nobel Peace Prize winner, received a lifetime achievement award bearing Ali's name.
Carter was unable to attend, and his son Chip accepted the award on his father's behalf. The former president, who turned 89 on Tuesday, has crisscrossed the world since leaving the White House more than three decades ago to promote efforts to resolve conflict, promote democracy, protect human rights and prevent disease in many of the world's poorest countries.
Chip Carter called Ali a close family friend and said the boxing great used his influence to help promote peace and human rights in Africa during the Carter presidency. Ali stood to shake hands with Chip Carter at the end of the ceremony.
Carter said his parents have spent their lives speaking up "for the rights of those who have the least."
"They are leading advocates for human rights and peace in the world," he said. "...They sometimes failed, they sometimes succeed. But they always try to do the right thing, to right the wrongs and to alleviate the suffering that they find."
Bolton received the Muhammad Ali Humanitarian Award for Gender Equity.
The singer-songwriter brought the crowd to its feet with his version of "When a Man Loves a Woman."
He was recognized for his work with women's groups and members of Congress to pass the Violence Against Women Act. He continues to raise awareness about domestic violence and has helped enlist other men to take up the cause of eradicating it.
"There is no mistaking it, gender equality is the only acceptable future for our world," he said.
Meanwhile, six young adults and teenagers from around the world received Ali Humanitarian awards for exemplifying core principles espoused by Ali. Those principles are confidence, conviction, dedication, giving, respect and spirituality.
Winners included a 25-year-old Ugandan who formed an anti-poverty organization that promotes self-reliance and an American teenager who started a foundation that has provided shoes to thousands of homeless and disadvantaged children.
