Men slide in the mud during the Boryeong Mud Festival at Daecheon Beach in Boryeong, South Korea, Saturday, July 22, 2017. The 20th annual mud festival features mud wrestling and mud sliding. (Photo by Ahn Young-joon/AP Photo)

Robert Galvan, who is on death row for murder, speaks to members of the media at the Adjustment Center yard during a media tour of California's Death Row at San Quentin State Prison in San Quentin, California December 29, 2015. America's most populous state, which has not carried out an execution in a decade, begins 2016 at a pivotal juncture, as legal developments hasten the march toward resuming executions, while opponents seek to end the death penalty at the ballot box. (Photo by Stephen Lam/Reuters)

Revellers take part in an annual block party known as “Cordao de Prata Preta”, one of the many carnival parties to take place in the neighbourhoods of Rio de Janeiro, February 6, 2016. (Photo by Pilar Olivares/Reuters)

Wide-angle category winner. Part of the Illusion by Marcus Blatchford (UK). Location: National Dive & Activity Centre, Chepstow, Wales. “This is the deepest inland dive centre in the UK. The dive plan was to explore the deep end, but this time I dived ‘unplugged’ (without my strobes). With the exception of this change to my camera technique, there were no planned shots I wanted to achieve – just a fun dive with ad-hoc photos along the way. Shortly after this photo was captured, in 6C water and two hours of decompression ahead of us, we turned and started the long ascent back to the surface”. (Photo by Marcus Blatchford/Underwater Photographer of the Year 2016)

A man dressed in red-white-and-blue sits on the curb during a protest against President-elect Donald Trump, Wednesday, November 9, 2016, in Seattle's Capitol Hill neighborhood. (Photo by Ted S. Warren/AP Photo)

A protester wearing high heels during a demonstration to support International Day for the Elimination of Violence Against Women in Santiago, Chile, November 25, 2016. (Photo by Pablo Sanhueza/Reuters)

This picture taken on October 20, 2016 shows students practising wushu at the Tagou martial arts school in Dengfeng. China is investing hugely in football training and has vowed to have 50 million school- age players by 2020, as the ruling Communist party eyes “football superpower” status by 2050. (Photo by Nicolas Asfouri/AFP Photo)

A pair of young visitors rushes through a tunnel of colored lights at the annual Garden of Lights display at Brookside Gardens on December, 06, 2015 in Silver Spring, MD. (Photo by Bill O'Leary/The Washington Post)