Members of the U.S. Army 173rd Airborne Brigade stand at attention as a Ukrainian folk dance group performs at the opening ceremony of the “Rapid Trident” NATO military exercises on September 15, 2014 near Yavorov, Ukraine. The two-week exercises include participating units from a variety of NATO and NATO-associate countries as well as Ukrainian troops. Meanwhile fighting between pro-Russian separatists and Ukrainian armed foces has flared again in eastern Ukraine in a battle for the control of Donetsk airport despite the tenuous ceasefire. (Photo by Sean Gallup/Getty Images)

In this August 21, 2017 photo released by the U.S. Defense Department, Qatari special operations personnel conduct a military free-fall Friendship Jump over Qatar. The U.S. military has halted some exercises with its Gulf Arab allies over the ongoing diplomatic crisis targeting Qatar, trying to use its influence to end the monthslong dispute, authorities told The Associated Press on Friday, October 6, 2017. (Photo by Staff Sgt. Trevor T. McBride/ U.S. Air Force via AP Photo)

Eddie Ladd and Gwyn Emberton perform as Dylan and Caitlin Thomas in “Caitlin” at the Lauriston Hall, Edinburgh, Scotland on August 25 2017. (Photo by Mary Turner/Reuters)

An artist gets ready backstage to perform an Indian art form of dance called “Ottamthullal” at the annual eight-day long Vrischikolsavam festival, which features a colourful procession of decorated elephants along with drum and trumpets concerts, at Sree Poornathrayeesa temple in Kochi, India, December 7, 2018. (Photo by Sivaram V/Reuters)

Indian Air Force personnel parade during the 85th Air Force Day celebrations at Hindon Air Force base in Ghaziabad on October 8, 2017. (Photo by AFP Photo/Stringer)

Belarusian schoolchildren, who are members of a pro-government Young Pioneer movement, perform with drums as they take part in a meeting to mark the 95th anniversary of their organisation in Minsk, Belarus May 19, 2017. (Photo by Vasily Fedosenko/Reuters)

A Colombia fan clearly regrets invading the pitch as she is chased by a large security guard during the International Friendly match between Australia and Colombia at Craven Cottage on March 27, 2018 in London, England. (Photo by Charlotte Wilson/Offside/Getty Images)

People with a South Korean flag waves as fireworks get off outside the stadium during the opening ceremony of the Pyeongchang 2018 Winter Olympic Games at the Pyeongchang Stadium on February 9, 2018. (Photo by Martin Bernetti/AFP Photo)