Garbage containers burning at the Aragón street barricade during the demonstration in Barcelona, Spain on February 18, 2021. Third night of protests and riots in response to the arrest and imprisonment of rapper Pablo Hasel accused of exalting terrorism and insulting the crown from the content of the lyrics of his songs. (Photo by Paco Freire/SOPA Images/Rex Features/Shutterstock)

A protester uses molotov cocktails against riot police during May Day protests on May 1, 2010 in Athens, Greece. (Photo by Milos Bicanski /Getty Images)

Horse racing is part of Naadam, a festival organized every July in Mongolia to celebrate the People’s Revolution. Using children as jockeys in such races has a centuries-long tradition. Boys and girls as young as 5 (although the law imposes a minimum age limit of 7) ride in races that can be dangerous, with hundreds of horses running across the steppe at distances of 12 to 28 kilometres at great speeds. (Photo by Tomasz Gudzowaty)

Groupama Sailing Team, skippered by Franck Cammas of France during leg 1 of the Volvo Ocean Race to Cape Town on November 6, 2011. (Photo by Yann Riou/Groupama Sailing Team/Volvo Ocean Race via Getty Images)

A Palestinian demonstrator jumps in the air during clashes with Israeli riot police on May 13, 2011 in the East Jerusalem neighbourhood of Issawiya, Israel. Palestinians began marking the “Nakba” or “catastrophe” which befell them following Israel's establishment in 1948. (Photo by Uriel Sinai/Getty Images)

People lay flowers for and mourn the anti-government protesters who were killed in the past weeks’ clashes with riot police.

Participants dressed as Santa Claus gather shortly before the 4th annual Michendorf Santa Run (Michendorfer Nikolauslauf) on December 9, 2012 in Michendorf, Germany. Over 800 people took part in this year's races that included children's and adults' races. (Photo by Sean Gallup)

A Thai villager runs with a bullock during a catching a bullock competition as part of the annual bullock cart racing festival in Phetchaburi province, Thailand, 21 February 2016. The annual bullock cart race festival held to celebrate the end of the harvest season. (Photo by Rungroj Yongrit/EPA)