Challenger Bulgarian heavyweight boxer Kubrat Pulev (R) lies in the ring after being knocked down by Ukrainian WBA, WBO, IBO and IBF heavyweight boxing world champion Vladimir Klitschko (L), who celebrates with his brother Vitali (2nd L), as referee Tony Weeks checks on him after their title fight in Hamburg, November 15, 2014. World heavyweight champion Vladimir Klitschko knocked out Bulgarian challenger Kubrat Pulev with a fierce left hook in the fifth round on Saturday to retain his IBF title and end his opponent's unbeaten record. (Photo by Fabian Bimmer/Reuters)

The Rio de Janeiro Olympics kick off on August 5 for some two weeks of competitive games drawing athletes as well as audiences from around the world. As they prepare to cover the event, Reuters photographers look back on their favourite pictures from past Olympics where they captured the action on the ground as well as the participants' tears and joy that followed. (Photo by Lucy Nicholson/Reuters)

Thierry Neuville of Belgium drives his Hyundai i20 Coupe WRC during day 3 of Rally Mexico, in Leon, Guanajuato, Mexico, 14 March​ 2020. (Photo by Reporter Images/EPA/EFE)

A pitch invader takes the field during the fourth quarter in Super Bowl LV between the Tampa Bay Buccaneers and the Kansas City Chiefs at Raymond James Stadium on February 07, 2021 in Tampa, Florida. (Photo by Matthew Emmons/USA TODAY Sports)

(L-R) Ryan Regez of Switzerland, Tyler Wallasch of USA, Sandro Siebenhofer of Austria and Ferdinand Dorsch of Germany during the men's quarterfinal heat 4 during the men's Ski Cross final at the FIS Freestyle Ski World Cup event in Idre, Sweden 23 January 2021. (Photo by Pontus Lundahl/EPA/EFE)

Copperhead ridden by Harry Cobden falls during the RSA Insurance Novices' Chase (Grade 1) at Cheltenham Racecourse on March 11, 2020 in Cheltenham, England. (Photo by Tom Jenkins/The Guardian)

Mammoet Rallysport's Martin Van Den Brink and Co-Driver Wouter De Graaff in action surrounded by camels during stage 10, Neom to AlUla, Saudi Arabia on January 13, 2021. (Photo by Hamad I Mohammed/Reuters)

Children carry firewood on their heads and walk homewards on the outskirts of Rae Bareli, India, Thursday, December 17, 2020. (Photo by Rajesh Kumar Singh/AP Photo)