A handout photo made available by Limex Images of Pete McLeod of Canada (R) and Kirby Chambliss of the United States flying over the city of Kazan prior to the fifth stage of the Red Bull Air Race World Championship in Russia on August 22, 2018. (Photo by Joerg Mitter/EPA/EFE/Limex Images)

A stroller walks his dogs in an autumnally colored forest in Cuxhaven, nothern Germany on November 7, 2018. (Photo by Patrik Stollarz/AFP Photo)

With her husband, Brazil's new President Jair Bolsonaro in the background, Brazil's new first lady Michelle Bolsonaro gives a military salute from the Planalto Presidential palace, in Brasilia, Brazil, Tuesday, January 1, 2019. (Photo by Silvia Izquierdo/AP Photo)

Soldiers on exercise in Kenya. The image, by Sergeant Dek Traylor, is among the section winners in the UK Army Photographic Competition 2018. (Photo by Sergeant Dek Traylor/PA Wire Press Association)

Viking re-enactors representing the rival armies of the Vikings and Anglo-Saxons skirmish near Clifford’s Tower during the Jorvik Viking Festival on February 23, 2019 in York, England. The annual Jorvik Viking Festival held in York is recognised as the largest event of its kind in Europe. This year the festival remembers the role that the Viking women played during those turbulent times. (Photo by Christopher Thomond/The Guardian)

Participants pose for photographs as they take part in a “Hat Walk” during London Hat Week in London, Britain on April 7, 2019. (Photo by Simon Dawson/Reuters)

A skier in a festive costume attempts to cross a pool of water at the foot of a ski slope while competing in the annual Gornoluzhnik amateur event to mark the end of the ski season at the Bobrovy Log ski resort in the suburbs of the Siberian city of Krasnoyarsk, Russia, April 14, 2019. (Photo by Ilya Naymushin/Reuters)

Sun Rongchun, 57, exercises with an improvised cervical traction device attached to a high bar at a sports complex in Shenyang, Liaoning province, China on April 9, 2019. (Photo by Sheng Li/Reuters)