Two F-15E Strike Eagles wait to receive fuel from a KC-135R Stratotanker during exercise Red Flag 15-1 on their way to Nellis Air Force Base, Nev., Jauary 23, 2015. The F-15s are assigned to the 4th Fighter Wing. U.S. (Photo by Airman 1st Class Aaron J. Jenne/Reuters)

An artist performs with a lion during the presentation of the new international show “Extreme arena” at the Ukrainian National Circus in Kiev, Ukraine, 15 September 2016. The show will be staged from 15 September to 11 December 2016. (Photo by Roman Pilipey/EPA)

A woman touches a robot at the 2018 World Robot Conference in Beijing on August 15, 2018. The conference will be held from 15 to 19 August and will include a conference on robotics, an exhibition and a robot competition with the participation of robotics enterprises to showcase their robot products. (Photo by Wang Zhao/AFP Photo)

Rapper Nicki Minaj attends TIDAL X: 1015 on October 15, 2016 in New York City. (Photo by Brad Barket/Getty Images for TIDAL)

Visitors dressed in superhero costumes attend the Paris Comics Expo at the Parc Floral in Paris, France, April 15, 2016. (Photo by Charles Platiau/Reuters)

A dog jumps over an obstacle during the International Agility Riga Cup competition in Riga, Latvia, August 15, 2015. (Photo by Ints Kalnins/Reuters)

Festive decorations and illumination lights for the upcoming New Year and Christmas season are unveiled in Minsk, Belarus on December 15 , 2019. (Photo by Vasily Fedosenko/Reuters)

A Fulani woman fixes her head scalf on the street of Dapchi, Yobe state, Nigeria on February 27, 2018. (Photo by Afolabi Sotunde/Reuters)