Muhammad Ali is one of the greatest athletes of the 20th century and an icon to generations of boxers. A three-time heavyweight world champion, he also served as an activist and philanthropist.

Ali, the self-styled "Greatest," won an Olympic gold medal at age 18 and amassed 56 wins - half of them knockouts. His arrogance was matched by incredible talent as he entertained millions around the world with his charisma.

1. He was born in Louisville

On January 17, 1942, Muhammad Ali was born into segregated Louisville, Kentucky and raised with racism and racial prejudice. Throughout his life he actively fought for his rights and upheld his convictions.

He was a renowned boxer and social activist renowned for his advocacy on race relations, religious freedom, and racial justice. To many around the world he was an inspiration; through his words and deeds he transformed it for the better.

He began his boxing career on Grand Avenue, a street known to generations of Louisville natives. Here, he honed his craft as an athlete and won gold at the 1960 Rome Olympics. Since then, he's returned often for training sessions in Louisville.

2. He was a Muslim

Ali's conversion to Islam was a daring and controversial step, according to David Remnick's biography of him. He was drawn to the Nation of Islam's message of racial pride, self-sufficiency and almost militant sense of manhood that it preached, says Remnick.

He eventually converted to mainstream Sunni Islam and was given the name Muhammad Ali - meaning "beloved of God" - as a reminder of his commitment to the religion.

He was a staunch Muslim and advocated for racial justice throughout his life. Additionally, he spoke out in support of internationalist causes.

3. He was a draft evader

On this week fifty years ago, Muhammad Ali refused induction into the United States Army to fight in Vietnam. His decision was based on his religious beliefs against war and served as a conscientious objector.

At the time, civil rights leader and boxer John Farrior's refusal to come forward was seen as an incendiary statement and served as a catalyst for anti-war demonstrations across America.

Ali's request for a conscientious objector exemption was initially turned down by the draft board, but ultimately upheld by the Supreme Court in 1971. This landmark case served as an early example of activists refusing to fight for causes they believed in.

4. He was a boxer

Ali was a boxing great who achieved three times world champion status. Not only did his skills and talent in the sport make him unbeatable, but he also used his position to fight against discrimination and inequality.

He fought against the idea that Black athletes had to submit to White authority. He joined the Nation of Islam, a Black Muslim organization which opposed American racism and advocated for racial justice.

His refusal to serve in the military was an act of civil disobedience and he publicly opposed the Vietnam War.

His position was controversial, and he was eventually found guilty of failing to serve in the military. Fortunately, this conviction was overturned by the U.S. Supreme Court in 1971.

5. He was a philanthropist

Muhammad Ali was an inspirational humanitarian and peace advocate who dedicated his life to improving the lives of people throughout the world. He worked tirelessly to promote religious tolerance, civil rights and inter-cultural understanding.

He had long been an opponent of apartheid in South Africa, and used his fame to raise awareness about racial and global injustices. Throughout the years he traveled the globe, speaking out against violence and poverty, meeting with leaders from different religious traditions, as well as making goodwill missions to Iraq, North Korea, Cuba, and Afghanistan.

Though he was diagnosed with Parkinson's disease in 1984, he continued to make public appearances and donate funds for charities. He visited numerous soup kitchens and hospitals while raising funds for the Muhammad Ali Parkinson Center in Phoenix, Arizona. Furthermore, he participated in "Celebrity Fight Night" to generate funds for Barrow Neurological Institute.

6. He was a humanitarian

Muhammad Ali was not only one of the greatest boxers ever, but a renowned humanitarian as well. Through his lifetime work, Ali helped promote world peace, civil rights, cross-cultural understanding, interfaith relationships, humanitarianism and hunger relief around the world.

He made several goodwill missions to Afghanistan and North Korea; provided over $1 million in medical aid to Cuba; traveled to Iraq during the first Gulf War to secure the release of fifteen United States hostages; and finally made a trip to South Africa where he met Nelson Mandela upon his release from prison.

He was an outspoken champion for religious and civil rights, including as a conscientious objector. He challenged the legitimacy of the Vietnam War by refusing to enlist in its military while few prominent Americans were doing so. As such, his legacy continues to inspire change-makers around the world today.

7. He was a celebrity

Muhammad Ali was a legendary figure in boxing, and he loved being challenged by the media. Despite his celebrity status, Ali never shied away from speaking out on issues that mattered to him - such as racial equality or social justice.

He used his celebrity status to advocate for peace, cross-cultural understanding and interfaith harmony around the world. He saved hostages from Iraq and made goodwill missions to Cuba and North Korea, using it as a platform to spread goodwill around the globe.

He received the Presidential Medal of Freedom in 2005 and Amnesty International's lifetime achievement award. Additionally, he served as a United Nations Messenger of Peace.

8. He was a comedian

Muhammad Ali was not only one of the greatest boxers to ever fight in a ring, but he also had a knack for comedic invention. A master of words and poetry, Ali created some classic punch lines that have endured throughout time.

He even got playful on Candid Camera with his jokes, playing pranks on school kids in the process.

He was renowned for tying a bow tie around his mouth. Additionally, he was an Oscar winner.

9. He was a boxer

Muhammad Ali, three-time heavyweight boxing champion and icon in American culture, is remembered not only as one of the greatest athletes ever but also a social activist, philanthropist and humanitarian.

Muhammad Ali had a profound effect on American culture by standing up against racism and discrimination, inspiring others to follow his values and principles. From teaching tolerance and acceptance, to feeding the hungry or aiding children in need, his efforts always sought to make our world a better place for all.

He joined the Nation of Islam and took on Muhammad Ali's slave name, adopting their teachings on religious freedom and racial justice. Through protesting segregation and challenging the legitimacy of the Vietnam War, Muhammad Ali was ultimately suspended from boxing for three years due to this act of civil disobedience.

10. He died in 2016.

Muhammad Ali, the greatest boxer of all time, passed away in 2016 at 74 years old. His passing sparked an extraordinary outpouring of sorrow and admiration around the world from world leaders to celebrities and athletes.

Ali's career spanned three decades, featuring twenty-two professional boxing championship bouts. Additionally, he became a renowned public speaker and advocate for civil rights and the Vietnam War.

On June 3, 2016, he succumbed to Parkinson's disease after a long and hard battle. In his final weeks, he made a public plea for people to understand more about this degenerative neurological condition and how it impacts patients.