Aug. 13, 2012 -- The Games of the XXX Olympiad have been filled with firsts, starting with London being the first city to have hosted the modern Olympic Games three times (1908, 1948 and 2012). With the Olympic torch now extinguished, take a look at some Olympians who made history this summer.
Michael Phelps, who dominated at the 2004 Athens and 2008 Beijing Games, cemented his place in history at the London Olympics. By winning four golds and two silvers, he collected a total of 22 medals, becoming the most decorated Olympian of all time.
The 27-year-old Baltimore swimmer retired with twice as many golds (18) as any other Olympian.
In London he was presented with the FINA (Federation International de Natation) lifetime achievement award, "The greatest Olympic athlete of all time."
He retired with no regrets. "I did everything I wanted to and finished my career how I wanted to," Phelps told reporters.
Thirty-six female boxers from 23 different nations fighting across three weight divisions made history in London: They signed the death of the Games' last male-only sport.
Nicola Adams from Great Britain became the first gold medalist in women's boxing at the Olympics, followed by boxers Katie Taylor from Ireland and Claressa Shields from the United States.
"It's nice to have a bit of recognition for all the years I've been training. I used to look up to Muhammad Ali, and it's a great feeling to know that now kids who are just starting in the sport will have a female to look up to as well," Adams said.
Jamaican runner and fastest man in the world Usain Bolt anchored himself into history by becoming the first man ever to win the 100-meter and 200-meter gold medals at consecutive Olympic games.
He then won a third gold for the second successive Olympic games by leading his 4x100-meter relay team to a new world record.
"I'm now a living legend. I'm also the greatest athlete to live," 25-year-old Bolt said.
Gymnast Gabby Douglas made history by becoming the first African-American woman to win the all-around event in the women's gymnastics competition at the Olympics.
Legendary gymnastics coach Bela Karolyi praised Douglas' gold-winning performance and the example she set for future athletes.
"Thousands and thousands of African-American kids are going to go into gymnastics because of her, because they will want to be the new Gabby Douglas," Karolyi said, according to the Chicago Tribune. "With Mary Lou in 1984, her popularity doubled the number of gymnastics participants in this country. I expect a similar effect with Gabby. She came out of nowhere and is now an explosion."
She came last in the final heat of the 800-meter, yet Sarah Attar, dressed in a long-sleeved green training top, long jogging bottoms and a white hijab, made history by being the first Saudi Arabian woman ever to be allowed by her country to run in the Olympics.
"It is a historic moment. I hope it will make a difference. It is a huge step forward," Attar said.
In a series of women firsts, London 2012 marked the first time conservative Islamic nations Qatar, Saudi Arabia and Brunei allowed their female athletes to compete at the Games.
Great Britain's Ben Ainslie sailed into Olympic history, becoming the most decorated Olympic sailor of all time.
Sixteen years after winning a silver at the Atlanta 1996 Games, the 35-year-old triumphed on home waters, winning his fourth straight gold.
Ainslie was chosen to carry the flag for the British team at the London 2012 Olympic Games closing ceremony.
As she won the women's kayak single 500-meter semifinal against women nearly half her age, 47-year-old Josefa Idem from Italy entered Olympic history, becoming the first woman to compete in eight Olympic Games.
Idem, who won an Olympic bronze medal in Los Angeles in 1984 when she was only 19, began her three-decade career in her native West Germany, but became a naturalized Italian citizen in 1992.
Four years later she claimed bronze in Atlanta, then gold in Sydney in 2000 and silver at both Athens (2004) and Beijing (2008).
In London, the Italian kayaker finished her final race of career in fifth place, just three tenths of a second from a bronze medal and under two seconds from gold.
"It's never too late to dream. Never too late to get going. This is the message I wish to leave," Idem said.
South Africa's Oscar Pistorius made history by becoming the first amputee sprinter to compete at any Olympics.
The 25-year-old double-amputee runner, four-time Paralympic champion, ran on his carbon-fiber blades in the men's 400-meter and was part of South Africa's 4x400-meter relay team.
"It has been an unbelievable experience. I didn't come here to prove a point. I wanted to do the best I could possibly do," Pistorius said.
Chosen to carry South Africa's flag at the closing ceremony for the London Olympics, Pistorius will defend his 100-meter, 200-meter and 400-meter titles at the Paralympic Games in London later in August.
As he reclaimed the 400-meter hurdles crown, 34-year-old Felix Sanchez from the Dominican Republic became the oldest-ever winner of an Olympic Games sprint event.
Sanchez took gold at Athens eight years ago but was not widely considered to be a medal contender this time around.
"No one expected this. A lot of people said I should retire, but I stuck with it," Sanchez said.
Russia's Evgeniya Kanaeva wrote her name in the record books by becoming the most successful rhythmic gymnast in Olympic history.
The 22-year-old is the first woman to win two Olympic rhythmic gymnastics all-around titles, winning at the 2008 Beijing and 2012 London Olympics.
"I have worked so hard for the last four years. I have worked hard throughout my whole childhood to be where I am today," Kanaeva said.
As they won the women's doubles champions at London 2012, Venus and her sister Serena Williams became the the greatest Olympic tennis players ever. The American pair have accumulated four gold medals each.
Venus won a singles gold medal at the 2000 Sydney Olympics, and the pair won the doubles gold medal that year as well. They won the doubles at the 2008 Beijing Olympics.
In London, Serena equaled her sister in singles competition by winning the gold. Less than 24 hours later, Serena and Venus took home the gold in doubles.
"For us, it's so exciting winning the gold together. For me, it was amazing to watch Serena from the stands and see her complete the golden slam," Venus said.
U.S. athlete Manteo Mitchell performed heroically in the 4x400-meter relay preliminaries by running on a broken leg. The 25-year-old had broken the left fibula bone running the first leg in the preliminary round.
"As soon as I took the first step past the 200-meter mark, I felt it break. I heard it. I wanted to just lie down," Mitchell said.
Instead, he just ran on it. "It felt like somebody literally just snapped my leg in half. It hurt so bad. I'm pretty amazed that I still split 45 seconds on a broken leg," Mitchell said.
Without Mitchell's courage and determination to finish the run, the American team would have not been able to be at the starting line in the final, where it won a silver medal.
The U.S. men's basketball team made history by thrashing the Olympics record for most points scored in a game. The Americans demolished the Nigerian team 156-73.
With the London 2012 Olympics being the most digitally connected event ever, self-proclaimed living legend Usain Bolt also triumphed on the Internet.
After his 200-meter victory, the Jamaican Olympian set a new Twitter Olympic conversation record with more than 80,000 tweets per minute. Bolt himself tweeted to his 1.3 million followers: "Thanks to all my real fans and people who believe in me. I am now a living legend that's for sure."