It will be the end of an era for athletics on Saturday when Usain Bolt races for the last time in the men's 4x100 metres relay at the World Championships.
The Jamaican is hoping to step away from the track having won his 20th global championship title, something he was denied last week when he finished third in the 100m behind American Justin Gatlin.
Fans flocking to the London Stadium on Saturday will probably be treated to a double dose of the 30-year-old sprint legend as Bolt plans to take part in the relay heats in the day's first session.
There will be a fair amount of emotion from the stands as Mo Farah also runs in his last track race - the 5,000 metres final.
The Briton is aiming to complete an unprecedented World Championship triple-double, having retained his 10,000m title on the first day - the home nation's only medal.
The penultimate day of the championships also has former 100 metres hurdles champion Sally Pearson of Australia going up against world record holder Kendra Harrison of the US for the title.
The decathlon reaches its climax with the traditional 1,500m to close the multi-discipline event.
There are also gold medals to be won in the women's high jump and the men's javelin.