These stunning pictures show a normally vicious tiger calmly swimming in a pool of algae, on Jule 9, 2014. The powerful cat takes a refreshing break by taking a dip in the bright green algae. But it looks like this big cat is scared of getting his head wet as he strains to keep it above the water. After splashing around for a bit the tiger gets out and tries to air-dry with specks of the vegetation dripping off his fur. The striking pictures were taken at Copenhagen zoo by snapper Soren Lundgren Neilson. (Photo by Soren Nielsen/Caters News)

A prisoner from the Pedrinhas prison is carried to receive medical help after he was injured during a fight between rival gangs inside the jail, in Sao Luiz, capital of Maranhao state, January 8, 2014. The recent posting on a major Brazilian news website of a video filmed last December 17 by Pedrinhas prisoners of the decapitated and tortured bodies of rival inmates inside the jail has highlighted some of the problems present in the country's prison system which houses nearly twice as many prisoners as its capacity, according to official statistics. (Photo by Douglas Cunha/Reuters/O Estado do Maranhão)

Singer Katy Perry arrives at the Metropolitan Museum of Art Costume Institute Gala 2015 celebrating the opening of “China: Through the Looking Glass” in Manhattan, New York May 4, 2015. (Photo by Lucas Jackson/Reuters)

Chase Elliott (9) makes a pit stop during the NASCAR Xfinity series auto race at Chicagoland Speedway, Sunday, June 21, 2015, in Joliet, Ill. (AP Photo/Nam Y. Huh)

Steam emerges from a cooling tower of the nuclear power plant Leibstadt near Leibstadt, Switzerland, November 18, 2014. (Photo by Arnd Wiegmann/Reuters)

The Pink Floyd inflatable pig floats next to Broadcasting House to promote their new exhibition at the V&A museum, in London, Britain May 10, 2017. (Photo by Neil Hall/Reuters)

In this June 12, 2017 photo, a woman stands in front of a mural on the slope in Central district, Hong Kong. Once known as Victoria after the British queen, Hong Kong island's waterfront formed the core of the British settlement after Hong Kong island was handed over as a colony in 1842. Today as Hong Kong approaches the 20th anniversary of its return to China, it remains a bustling commercial and financial center as well as the location of the main government offices. However, along the streets that angle sharply upward toward the mountains above, a more relaxed pace of life endures. (AP Photo/Kin Cheung)

In a photo taken on July 6, 2017 soldiers of the Korean People' s Army (KPA) watch a fireworks display as part of celebrations marking the July 4 launch of the Hwasong-14 intercontinental ballistic missile, in Pyongyang Fireworks lit up the sky over Pyongyang' s Juche Tower as North Korea celebrated its launch of intercontinental ballistic missile, a milestone in its decades- long weapons drive. On July 4 – the United States' Independence Day – it launched a Hwasong-14 rocket that analysts and overseas officials said had a range of up to 8,000 kilometres, which would put Alaska and Hawaii within reach. (Photo by Kim Won-Jin/AFP Photo)