Stormtrooper Jacob French is pictured on day 5 of his over 4,000 kilometre journey from Perth to Sydney approximately 25 kilometres from Mandurah on July 15, 2011 in Perth, Australia. French aims to walk 35-40 kilometres a day, 5 days a week, in full Stormtrooper costume until he reaches Sydney. French is walking to raise money for the Starlight Foundation - an organisation that aims to brighten the lives of ill and hostpitalised children in Australia. (Photo by Paul Kane/Getty Images)

Derrick Campana kneels beside Angel Marie, a three legged mini horse who wears a prosthetic leg made by Campana, at Animal Ortho Care in Sterling, Virginia, U.S., March 27, 2017. (Photo by Kevin Lamarque/Reuters)

Kurt Arrigo is Malta’s most eminent and one of the world’s finest marine photographers. ­­His illustrious and diverse career has seen him capture dramatic action at elite international sporting events.

Deadwood is pictured in the onetime spa and resort town Epecuen, November 5, 2015. Over the past few years the town of Epecuen, located 550 km (341 miles) southwest of Buenos Aires, has been attracting tourists with its eerie apocalyptic atmosphere after a flood submerged it in salt water for more than two decades. Photo by Enrique Marcarian/Reuters)

Growing cities, overuse of fertilizers and factory wastewater have degraded China's water supplies to the extent that half the nation's rivers and lakes are severely polluted. China aims to spend $850 billion to improve filthy water supplies over the next decade, but even such huge outlays may do little to reverse damage caused by decades of pollution and overuse in Beijing's push for rapid economic growth. Photo: Fishermen row a boat in the algae-filled Chaohu Lake in Hefei, Anhui province, June 19, 2009. (Photo by Jianan Yu/Reuters)

Stunning images taken by Sean Lenz, 19, and Kristoffer Abligaard, 20, show picturesque waterfalls transformed into vibrant rainbows of colour. The awe-inspiring images were created by clever use of long exposure photography and glow sticks floating through water. Photo: Picturesque waterfalls transformed into rainbows of colour. (Photo by Sean Lenz/Kristoffer Abildgaard)