A female Marine prepares to throw a practice grenade during Marine Combat Training (MCT) on February 21, 2013 at Camp Lejeune, North Carolina. Since 1988 all non-infantry enlisted male Marines have been required to complete 29 days of basic combat skills training at MCT after graduating from boot camp. MCT has been required for all enlisted female Marines since 1997. About six percent of enlisted Marines are female. (Photo by Scott Olson)

A wild leopard runs on the stairs as it tries to escape from a compound of a house in Kathmandu, Nepal June 1, 2016. (Photo by Navesh Chitrakar/Reuters)

A man poses for a photograph in front of a mural of Democrat US presidential nominee Hillary Clinton clad in a swimsuit bearing the colours of the US flag in West Footscray in Melbourne on July 30, 2016. An Australian mural of US presidential nominee Hillary Clinton in a revealing, stars and stripes swimsuit may be taken down, after it has reportedly been deemed offensive. (Photo by Paul Crock/AFP Photo)

A Somali Armed Forces member carries her ammunition during fighting between the military and police backed by intelligence forces in the Dayniile district of Mogadishu, Somalia September 16, 2017. (Photo by Feisal Omar/Reuters)

In this Saturday, February 18, 2017 photo, revelers take part in the “Guanabara Pearl” carnival street party on Paqueta Island in Rio de Janeiro, Brazil. Merry makers ferried across Guanabara Bay to Paqueta Island for the parade. (Photo by Mauro Pimentel/AP Photo)

Brain-on-a-chip. Dazzling in green and magenta this image shows the nerve fibres (in green) produced by neural stem cells (in magenta) as they grow on a synthetic gel. Captured by a technique known as confocal microscopy, the image is part of research shedding light on how tinkering with the environment can affect the way in which nerve fibres grow. (Photo by Collin Edington and Iris Lee/Massachusetts Institute of Technology/Wellcome Images)

Peacocks are seen covered in bags as a protection of their plume during transportation, in Xiangyang, Hubei province, China April 12, 2017. (Photo by Reuters/Stringer)

US President George W. Bush (R) and Russian President Vladimir Putin wave as the two presidents go for a ride in Putin's 1956 Volga before dinner 08 May 2005 at the his residence outside of Moscow. Bush hailed Russia's “bravery and sacrifice” in defeating Nazism, as he met Putin ahead of ceremonies marking the 60th anniversary of the end of World War II. Bush, who the previous day criticized the decades-long Soviet occupation of central Europe, said he was looking forward to the 09 May ceremony on Moscow's Red Square, to be attended by over 50 national leaders. (Photo by Tim Sloan/AFP Photo)