Juno, a Beluga whale, greets a young viewer at the Mystic aquarium in Connecticut, USA on December 5, 2015. (Photo by Tim Clayton/Corbis)

A woman walks with her baby past a PM militarized police soldier in position and aiming his rifle in Rocinha favela in Rio de Janeiro, Brazil on September 23, 2017. Although shooting was reported in the early hours of Saturday in Rocinha – for the seventh day running – officials said that Friday's deployment of 950 soldiers to reinforce police had brought the crisis under control. (Photo by Carl De Souza/AFP Photo)

The photography of Art Wolfe covers the globe, capturing landscapes, wildlife, and cultures from every continent; here he talks through a selection of his favourite images. Art Wolfe is an American photographer and conservationist. His photographs have been noted by environmental advocacy groups for their “stunning” visual impact. Here: Snowy owlets (Bubo scandiacus), Arctic National Wildlife Refuge, Alaska, USA. (Photo by Art Wolfe/Art Wolfe Stock)

In this April 4, 2014 file photo, a community policeman kicks a man who they alledge participated in an ambush against them near the town of La Concepcion, Mexico. The vigilante force was set-up by affected communities opposed to the construction of the La Parota hydroelectric dam. Two vigilantes were injured and one died. (Photo by Bernandino Hernandez/AP Photo)

Liu Chunxia, a supporter of Xu Zhiyong, one of China's most prominent rights advocates, is detained by policemen while she gathers with other supporters nearby a court where Xu's trial is being held in Beijing January 22, 2014. When dozens of activists unfurled banners across the country last March and April calling for officials to disclose their assets, they did so at the urging of one of China's most prominent rights advocates, Xu Zhiyong. Xu, 40, stands trial on Wednesday on a charge of “gathering a crowd to disturb public order” punishable by up to five years in prison. His case will almost certainly spark fresh criticism from Western governments over Beijing's crackdown on dissent. (Photo by Kim Kyung-Hoon/Reuters)

Amateur astronomer Bill Snyder has been involved with astrophotography since 2007. Photo: The Cygnus Wall is in the southern area of NGC7000 also known as the North America Nebula. It is approximately 1800 light years from Earth, and is in the constellation Cygnus. The Wall is an energized shock front and contains the most concentrated star formations in the nebula. The size of the North America Nebula is about 4 full moons. (Photo and caption by Bill Snyder)

A Ukrainian serviceman fires a 2S7 Pion self-propelled gun during military exercises near the village of Divychky in Kiev region, Ukraine, October 21, 2016. (Photo by Valentyn Ogirenko/Reuters)

Jockeys spur buffalos during the Makepung buffalo races at Jembrana in Bali, Indonesia on October 23, 2016. Makepung is a tradition for farmers to celebrate a bumper harvest in Bali. (Photo by Kadek Raharja/Xinhua/Barcroft Images)