Last updated at 12:46
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In pictures: Usain Bolt's Olympic journey

Newsround looks back at how the Lightning Bolt became the fastest Olympian in history.
Usain Bolt first blasted onto the Olympic scene in 2004 where he ran in the 200 metre race at the Athens games. But back then at just 17 years old, he wasn't fast enough to make it past the first round of the competition.
Usain Bolt at the Athens games in 2004.
In 2008 Bolt was back and this time he meant business in Beijing! In the 100 metre final he won gold and set a new world record running the distance in a super speedy 9.69 seconds.
Usain Bolt at the Beijing Olympics.
Next up in Beijing was the 200 metre final. Bolt blasted into first place taking home his second Olympic gold medal.
Usain Bolt at the Beijing Olympics.
Bolt then added a third gold to his collection by winning the men's 4x100 metre relay with his team mates. They ran the fastest time ever in an Olympic competition crossing the finish line in just 37.10 seconds.
Usain Bolt at the Beijing Olympics.
Four years later and Bolt was back at the Olympics. Before the London games started he said that he was only about 95 percent fit but Bolt still managed to win gold in the 100 metre final.
Usain Bolt at the London 2012 Olympics.
Three days later Bolt struck gold again, this time in the 200 metre final. He's now the only person to have ever won both the 100 metre and 200 metre finals twice in a row. It was a brilliant race for the whole Jamaican team who also took the silver and bronze medals.
Usain Bolt with Yohan Blake and Warren Weir.
Bolt won his sixth gold medal two days later in the 4x100m relay. He and teammates Yohan Blake, Nesta Carter and Michael Frater did it in style - crossing the line in world record time!
Jamaican 4x100m relay team pose by clock showing their new world record