A competitor participates in the Tough Mudder challenge near Henley-on-Thames in southern England May 2, 2015. (Photo by Eddie Keogh/Reuters)

Cheerleaders let their hair fly as they perform prior to a German first division Bundesliga soccer match between 1. FC Cologne and Bayern Munich in Cologne, Germany, March 4, 2017. (Photo by Michael Probst/AP Photo)

Omsin, a 25 year old femal green sea turtle, rests next to a tray of coins that were removed from her stomach after a surgical operation at the Faculty of Veterinary Science, Chulalongkorn University in Bangkok, Thailand, March 6, 2017. (Photo by Athit Perawongmetha/Reuters)

In this February 4, 2016 picture a masked participant of the traditional carnival parade poses in the streets of the village of Kippel in the Loetschental valley, southwestern part of Switzerland. During this sinister carnival, participants wearing wooden masks and animal furs, crowd the streets of the villages to scare the people. (Photo by Dominic Steinmann/Keystone via AP Photo)

Clash of the storms, New Mexico, US by Camelia Czuchnicki. “A clash between two storm cells in New Mexico, US, each with its own rotating updraft. The curved striations of the oldest noticeable against the new bubbling convection of the newer. It was a fantastic sight to watch and it’s the rarity of such scenes that keep drawing me back to the US Plains each year”. (Photo by Camelia Czuchnicki/Weather Photographer of the Year 2016)

A supporter of “Si” vote cries after the nation voted “NO” in a referendum on a peace deal between the government and Revolutionary Armed Forces of Colombia (FARC) rebels, at Bolivar Square in Bogota, Colombia, October 2, 2016. (Photo by John Vizcaino/Reuters)

The Arcaid awards highlight the best architectural photographs of the year – pictures of everything from giant arenas to tiny huts. The shortlisted photographs will be exhibited at the World Architecture Festival in Berlin, from 16 to 18 November, with an overall winner announced during the event’s gala dinner. Here: The stage for Haduwa Arts & Culture Institute, Ghana. Architect: (applied) Foreign Affairs. Nominated in the Sense of Place category. The open-air auditorium of this arts institute in Apam, Ghana, is built from ultra-strong curved bamboo. (Photo by Julien Lanoo)

In this photo taken on Friday, July 14, 2017, a student at a paramilitary camp for children calls the rank to attention outside Kiev, Ukraine. As the deadly conflict in eastern Ukraine entered its third year, some parents in Ukraine are anxious to make sure their children are ready to fight it, instead of swimming and playing volleyball. (Photo by Efrem Lukatsky/AP Photo)