A Yemeni soldier, pictured through a vehicle's windscreen, which was damaged by a bullet, gestures out of the window, in Marib, Yemen October 15, 2015. Marib is a city that is heavily armed even by the standards of Yemen, where the ready availability of weapons helped start civil war and is now preventing anyone coming out on top. Yemenis often say there are three guns for every person, a boast that has become an urgent concern in a country where the United Nations says the humanitarian situation is "critical". (Photo by Angus McDowall/Reuters)

A worker stands under the Airlander 10 hybrid airship during its unveiling in Cardington, Britain March 21, 2016. The world's largest aircraft has been unveiled for the first time since being fully assembled in the UK. The 302ft (92m) long Airlander 10 – part plane, part airship – was floated in a First World War hangar in Bedfordshire. (Photo by Darren Staples/Reuters)

Model feebee poses as part of art installation “Dazzle room” made by artist Shigeki Matsuyama at Room 32 fashion and design exhibition in Tokyo, Friday, February 19, 2016. Matsuyama's installation features a strong contrast of black and white, which he learned from dazzle camouflage used mainly in World War I, in Tokyo, Friday, Feb. 19, 2016. (Photo by Shuji Kajiyama/AP Photo)

Undated UK Ministry of Defence handout photo of an RAF Tornado GR4 which has been painted in Gulf War “desert pink” paint scheme to honour the aircraft type's almost continuous operational service since the Royal Air Force helped liberate Kuwait from Saddam Hussein's forces, taken by SAC Rose Buchanan, which has been shortlisted for the general public to pick their favourite RAF Image of the Year. (Photo by SAC Rose Buchanan/MoD Crown Copyright/PA Wire)

Ukrainian soldiers from the assault brigade inflict fire damage with a 120 mm mortar while supporting the assault operations of the infantry on April 19, 2024 in Ukraine. The country's Prime Minister Denys Shmyhal has warned its allies that if more military aid for Ukraine is not approved soon, such as the long-stalled aid package from the United States, it could usher in a “Third World War”. (Photo by Kostiantyn Liberov/Libkos/Getty Images)

Visitors look at a giant puppet of a grandmother sleeping on a bed inside St George's Hall in Liverpool, northern England July 23, 2014. The grandmother is one of two giant models made for a World War I commemorative event. (Photo by Nigel Roddis/Reuters)

People walk past the 23-foot “Unitled (LAMP/BEAR)” outdoor sculpture of a teddy bear by artist Urs Fischer April 8, 2011 in New York City. The 35,000 pound sculpture of a yellow teddy bear with a working lamp will be on display for five months in front of the Seagram Building in Manhattan. The sculpture is expected to sell for more than $10 million at Christie’s Post-War & Contemporary Evening Sale on May 11. (Photo by Mario Tama/Getty Images)