Gymnast Valeria Kurochkina from Yekaterinburg performs during the Circus of Our Childhood festival at the Yekaterinburg Circus in Yekaterinburg, Russia on December 7, 2019. The festival marks the centenary of establishing state circuses in Russia. (Photo by Donat Sorokin/TASS)

A General Atomics MQ-9 Reaper stands on the runway during “Black Dart”, a live-fly, live fire demonstration of 55 unmanned aerial vehicles, or drones, at Naval Base Ventura County Sea Range, Point Mugu, near Oxnard, California July 31, 2015. (Photo by Patrick T. Fallon/Reuters)

A Somali police officer arrests a suspected rebel member of the al Qaeda-affiliated al Shabaab among beach goers in Mogadishu. Al Shabaab claimed responsibility for today's pre-dawn attack on a Kenyan university campus near the Somali border. The following gallery examines who is al Shabaab. Here: Somali police officer (R) arrests a suspected rebel member (L) of the Al Qaeda-affiliated al Shabaab among beach goers at the Lido beach north of Somalia's capital Mogadishu March 23, 2012. (Photo by Feisal Omar/Reuters)

Employees work on a crane above an E-70 wind turbine manufactured by German company Enercon for La Compagnie du Vent during its installation at a wind farm in Meneslies, Picardie region, France July 31, 2014. (Photo by Benoit Tessier/Reuters)

The Flying Bull's P-38 Lockheed Lightning N25Y / 13 – Red Bull – Flying Legends Airshow 2012 Duxford (Photo by Rob Lovesey)

(L-R) Michael Kasrpowicz, Jason Gillespie, Brett Lee and Glenn McGrath of Australia re-enact the famous Beatles album cover at Abbey Road on July 19, 2005 in London, United Kingdom (Photo by Hamish Blair/Getty Images)

Two Bulgarian tourists pose in front of the Eiffel Tower in Paris on their last day in the capital on March 24, 2014. (Photo by Franck Fife/AFP Photo)

A woman walks past graffiti on a wall in the Williamsburg neighborhood of the borough of Brooklyn, in New York, September 16, 2014. The picture was taken through car window with raindrops. (Photo by Shannon Stapleton/Reuters)