“Rivers Forgotten” is a journey through the passages and portals of the underground waterways that lie unseen below cities. Self-taught photographer Jeremy Kai brings these forgotten landscapes to light. Photo: Beneath the Toronto area, 2011. (Photo by Jeremy Kai)

Legend by Damien Hirst in the gardens of Chatsworth House on September 9, 2011 in Chatsworth, England. The never before seen work by Hirst is part of the Beyond Limits exhibition of modern and contemporary sculpture displayed in the gardens of Chatsworth by Sotherby's between 9th September to 30th October 2011. (Photo by Christopher Furlong/Getty Images)

Death Muammar Muhammad Abu Minyar al-Gaddafi (7 June 1942 – 20 October 2011) in Misrata on October 20, 2011. The veteran strongman was killed on as new regime forces crushed the last pocket of resistance in his hometown Sirte, the National Transitional Council said. (Photo credit should read MAHMUD TURKIA)

A Royal Air Force search and rescue helicopter prepares to leaves RAF Valley as the search continues for the crew of cargo vessel The Swanland which sank off north Wales on November 27, 2011 in Anglesey, Wales. (Photo by Christopher Furlong/Getty Images)

A general view at the launch of Imitate Mordern: A Gallery With A Difference on March 10, 2011 in London, England.

A tiger jumps while being trained at the Tiger Temple in Kanchanaburi province, west of Bangkok, Thailand, February 25, 2016. Thailand's controversial Tiger Temple, dogged for years by talk that it supplies the black market and mistreats its animals, is fighting to keep the big cats after wildlife authorities rejected a bid to extend a zoo licence that expired in 2013. The Buddhist temple, home to more than 100 tigers, has been investigated for suspected links to wildlife trafficking and wildlife activists have accused it of illegal breeding of the animals. Thai wildlife authorities have sent ten of the temple's tigers to a wildlife sanctuary. But the temple, which bills itself as a wildlife sanctuary, has denied links to illegal trafficking, and wants to hold on to its tigers. (Photo by Chaiwat Subprasom/Reuters)

Elephant polo players in action during the King's Cup Elephant Polo event 2016 final between teams King Power (blue) and The Elephant Story, in Bangkok, Thailand, March 13, 2016. Team King Power won the annual charity event, which is now in its 14th edition. This year's edition involved 18 elephants brought from tourist trekking camps in Pattaya as well as some unemployed in Surin, and a total of 10 teams encompassing over 40 players, in this event directed at raising funds to improve the lives of elephants and elephant conservation. (Photo by Diego Azubel/EPA)