Katie Rose Hobbs and Kirsten Elizabeth Pobjoy of British Aerosuperbatics Wingwalking Team perform ballet in the air during Huangguoshu Waterfalls Flight Conference on August 3, 2018 in Anshun, Guizhou Province of China. Huangguoshu Waterfalls Flight Conference including 18 aircraft from seven aerobatic teams from all over the world kicked off on Friday. (Photo by VCG via Getty Images)

Servicewomen march during a rehearsal for the Independence Day military parade in central Kiev, Ukraine on August 20, 2018. (Photo by Gleb Garanich/Reuters)

Students from St Andrews University are covered in foam as they take part in the traditional Raisin Weekend in the Lower College Lawn, at St Andrews in Scotland on October 22, 2018. The “raisin weekend” stems from a gift of raisins (now flour and foam) traditionally given by a first year student to their academic “parents” in gratitude for their guidance. (Photo by Russell Cheyne/Reuters)

Women are reflected in a puddle as they walk across Red Square in Moscow, Russia on April 26, 2018. (Photo by Yuri Kadobnov/AFP Photo)

A German rifleman beside the corpse of a French soldier in a trench at Fort Vaux, France, 1916. (Photo by Hulton Archive/Getty Images)

Alvine Uva, right, wrestles the winner's sash from the hands of newly-crowned Miss BumBum 2018 Ellen Santana, left after winning the Miss Bumbum Brazil 2018 pageant in Sao Paulo, Brazil on November 5, 2016. (Photo by Splash News and Pictures)

A street entertainer waits for tourists in Havana, Cuba on October 2009. (Photo by Desmond Boylan/Reuters)

A Chicago Police Officer runs toward gunfire as looters break into downtown stores in the early hours of the morning on August 10, 2020. (Photo by RMV/Rex Features/Shutterstock)