Kurdish guard women from the civilian protection unit which supports the Democratic Forces of Syria, cheer near the Syrian town of al Houl in Hasaka province, after the Democratic Forces of Syria took control of the area, November 14, 2015. A U.S.-backed Syrian rebel alliance on Friday captured the town of al Houl in Hasaka province, which had been held by Islamic State militants, a spokesman for the Kurdish fighters, part of the grouping, said. It was the first significant advance against IS by the Democratic Forces of Syria, which was formed last month. (Photo by Rodi Said/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)

A Romanian female soldier adjusts her helmet before taking part in weapons training with US Marines female counterparts at the Capu Midia Surface to Air Firing Range, on the Black Sea coast in Romania, Monday, March 20, 2017. About 1,200 US and Romanian troops take part in the Spring Storm 17 exercise, meant to simulate defense of the Romanian Black Sea coastline and urban areas. (Photo by Vadim Ghirda/AP Photo)

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)

A team from Woody's Ice Cream shop wrangle a large inflatable dinosaur down the street during the Independence Day Parade in Fairfax, Virginia July 4, 2015. Americans marched in star-spangled parades, ran relay races, gathered for fireworks shows and crowned a new world hot dog eating champion as they celebrated Independence Day in traditional style on Saturday. (Photo by Jonathan Ernst/Reuters)

A wounded servicemen of Ukrainian Military Forces looks on after the battle with Russian troops and Russia-backed separatists in Lugansk region on March 8, 2022. The number of refugees flooding across Ukraine's borders to escape towns devastated by shelling and air strikes passed two million, in Europe's fastest-growing refugee crisis since World War II, according to the United Nations. (Photo by Anatolii Stepanov/AFP Photo)