An army tank fires during a firefight against militants linked to al Qaeda near the southern Yemeni city of Zinjibar May 30, 2012. (Photo by Reuters/Yemen's Defence Ministry)

A view of an installation as part of the “S.A.C.R.E.D” exhibition by Chinese artist Ai Weiwei during the 55th La Biennale of Venice, in the church of Sant'Antonin in Venice May 28, 2013. (Photo by Stefano Rellandini/Reuters)

A woman plays with a kitten inside of a line house in downtown Shanghai April 12, 2015. (Photo by Carlos Barria/Reuters)

Activists and supporters of Ukrainian nationalist groups light flares during a rally to mark the third anniversary of the Euromaidan Revolution in downtown Kiev, Ukraine, 21 November 2016. About one thousand activists took park in the rally during which they burned tires on the Independence Square, destroyed the Russian bank Sberbank and broke windows in the office of a Ukrainian politician Viktor Medvedchuk, according to Ukrainian media. (Photo by Roman Pilipey/EPA)

Bavarian farmers load their cows on a boat before they drive over the picturesque Lake Koenigssee, Germany, October 3, 2015. Before the winter season approaches the farmers have to drive their cattle down from their Alpine meadows to a narrow valley that can only be reached by boat. (Photo by Michael Dalder/Reuters)

A photographer has done her best to guess what her dog is daydreaming about – creating a series of fantasy adventures around her unaware pooch as he takes his daily naps. (Photo by Caters News)

A thrill-seeking storm chaser captured the precise moment these giant lightning bolts lit up dark skies in a series of incredible storms. (Photo by Craig Eccles/Solent News & Photo Agency)

British soldiers inspect a captured German place in the Horseguards' Parade, London during World War I in November 1914, with the London Eye in the background as a reminder of just how much has changed in the last 100 years. (Photo by Peter Macdiarmid/Getty Images)