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Sir Chris Hoy's career in pictures

We take a look back at Sir Chris Hoy's career, as the six-time Olympic champion announces his retirement from the sport.
The cycling Scot has won a staggering 11 world titles. Here he is at the 2004 World Championships in Melbourne, where he came out top in the men's 1km track time trial.
Chris Hoy (centre) wins gold in Melbourne
Here's Chris Hoy with our Ricky last summer! "Sir Chris was beaming after winning two gold medals at London 2012," said Ricky. "At a press conference I got to meet him and his proud parents Carol and David. It was an honour to meet him."
Chris Hoy with Newsround's Ricky
Christopher Andrew Hoy was born in Edinburgh in 1976. He was inspired to cycle at the age of six by the BMX scene in 1982 film ET! He won his first Olympic medal at Sydney 2000 - a silver in the team sprint alongside Craig MacLean (centre) and Jason Queally (right).
Chris Hoy, Craig MacLean and Jason Queally
Hoy's first gold medal came in 2002 when he won the 1km track time trial final at the Commonwealth Games in Manchester.
Hoy at the Commonwealth Games in Manchester
Four years later, at the 2008 Beijing Olympics, Hoy became the first British Olympian in 100 years to claim three golds at one Games. He won the keirin, team sprint and individual sprint - phew!
Chris Hoy poses with the gold medals won during the 2008 Beijing Olympic
The same year, Hoy collected his first Olympic gold medal at the Athens Games in the 1km track time trial.
Chris Hoy wins gold at Athens Olympics
...and being awarded a knighthood in the Queen's New Year Honours List.
Chris Hoy with the knighthood medal he received at Buckingham Palace
At those Games, he became the most successful Olympian in British history by winning his fifth and sixth gold medals in the keirin and team sprint events.
Chris Hoy with his gold medals at the London 2012 Games
Hoy announced his retirement at a news conference in Edinburgh on Thursday. He said: "It was not a decision I took easily or lightly, but I know it's the right one."
Chris Hoy
At London 2012, he enjoyed the honour of leading Team GB into the Olympic Stadium at the opening ceremony.
Chris Hoy leading Team GB at Olympic opening ceremony
That led to Hoy being voted BBC Sports Personality of the Year 2008...
Lewis Hamilton (left), Chris Hoy (centre) and Rebecca Adlington