A masked reveller hangs from an inflatable balloon during the first day of the carnival in Venice, Italy, January 23, 2016. (Photo by Manuel Silvestri/Reuters)

Ukrainian artist Dariya Marchenko works on a portrait of Russian President Vladimir Putin named “The Face of War” which is made out of 5,000 cartridges brought from the frontline in eastern Ukraine, in Kiev, July 23, 2015. The portrait will be presented along with a novel which will tell personal stories of six people involved in this project including Daria's own story and stories of people who helped her to collect shells from the frontline. Daria Marchenko calls her art approach philosophic symbolism where every element has its hidden meaning. In her works cartridges mean human's life that was brutally ended. (Photo by Gleb Garanich/Reuters)

An airplane is silhouetted at sunrise, seen from the suburb of Saint-Cloud, near Paris, France, 08 December 2016. Paris is undergoing a third day pollution spike, prompting the city to limit vehicle circulation. (Photo by Ian Langsdon/EPA)

Mr. Zhong Hua, of Johns Hopkins University School of Medicine, took this image of the peripheral nerves (those outside of the brain) in an 11.5-day-old mouse embryo, magnified five times. (Photo by Zhong Hua)

Friends of Li Guojun drive a homemade tank-shaped vehicle in Kangping county, China. Li, a farmer who is a fan of tanks, spent six months with help from his friends to construct the almost 20-foot vehicle which weighs 2.5 tons. (Photo by Sheng Li/Reuters)

Vocalist Laila Skovmand, a musician with Danish company Between Music, plays underwater in a tank during a rehearsal ahead of their UK premiere concert Aquasonic at the Tramway in Glasgow on Ocrober 25, 2017. (Photo by Robert Perry/PA Images)

Two men fight in San Jose, Costa Rica, during the Women's Day on March 8, 2014. (Photo by Jeffrey Arguedas/EFE/SIPA Press)

Audrey Mata from Washington D.C in the U.S. dressed as Princess Leia, comes face to face with a replica of R2-D2 at the 'For The Love of The Force' Star Wars fan convention in Manchester, northern England, December 4, 2015. (Photo by Phil Noble/Reuters)