Women were never allowed to compete in the Olympics until the Paris Games in 1900, when their participation in lawn tennis and golf events secured a position for female athletes in future Games.

The London 2012 Olympics signifies a new gender milestone with the debut of Women's Boxing, and it will also be the first Games in Olympic history with female athletes from every competing country.

African-American athlete Jesse Owens broke records and won several gold medals, shattering Hitler’s aim to use the 1936 Games as an example of the “new Aryan man.” Owens later befriended his German competitor in the long jump, Luz Long, and the pair's lap of honor became a symbol of the triumph of sportsmanship over Nazi ideology.

English doctor Ludwig Guttmann founded the International Wheelchair Games to help rehabilitate wounded veterans of World War II. Using sports therapy, he invited wheelchair athletes to compete, and the event eventually became the modern Paralympic Games.

As the first Olympics ever to be televised and include a brand endorsement by an athlete, the Rome Games ushered in a new era of commercialism and changed the way the world viewed its Olympians.

The Games also spotlighted a negative side of the competition with the first doping scandal, revealing how far some athletes would go to bring home the gold.

Tragedy infamously marred the Munich Games when 11 Israeli athletes were taken hostage and killed by Palestinian terrorists. Although the Olympics continued and the incident led to increased security, the message of international peace promoted by the Games was permanently damaged.

Human right was at the forefront of the Montreal Games after 22 African nations boycotted the Olympics because New Zealand was participating. Earlier that year, New Zealand sparked outrage among African countries when it sent its national rugby team to play in South Africa, which was under apartheid. This marked the first of several politically-motivated boycotts of the Olympics.

The 1992 U.S. Men's Olympic basketball team, nicknamed the "Dream Team" for its impressive line-up of the biggest names in basketball—Michael Jordan, Charles Barkley, and Patrick Ewing to name a few—was the first time active NBA players were recruited for an Olympic team. The team crushed the competition as it made its way towards the final (winning all eight games) and ultimately defeated Croatia to bring home the gold medal. Still today, the Dream Team is widely celebrated as the greatest team ever assembled in any sport.

Despite his struggles with Parkison's disease, former heavyweight boxing champion and Olympic gold medalist Muhammad Ali lit the Olympic flame during the opening ceremony of the 1996 Atlanta Games. It was an emotional start to the Olympics' Centennial.

A new medal was distributed to winners at the Athens Games, replacing the long-standing design by Italian sculptor Giuseppe Cassioli that incorrectly depicted the Roman Colosseum rather than a Greek venue. Olympic medals now feature the Panathinaiko Stadium in Athens, one of the world's oldest stadiums and the site of the first modern Olympic Games in 1896.

During the Beijing Games, champion American swimmer Michael Phelps and his teammates set a new world record in the medley relay event, awarding Phelps his eighth gold medal (the most won in a single Olympic Games) and pushing his medal count over that of his record-holding predecessor, Mark Spitz. Upon winning his eighth medal, Phelps had nothing but humble words for his audience: "Records are meant to be broken no matter what they are."