The Rio Tinto river in Spain crosses an ancient mining site which makes the water turn a variety of bright colours. Copper, silver and gold are mined here, as well as iron, which turns the water red. An ochre mix is responsible for the yellow tint of the rest of the river. (Photo by Olivier Jarry-Lancombe/Solent News)

A breeder puts a giant panda cub into a crib at Chengdu Research Base of Giant Panda Breeding in Chengdu, Sichuan province, September 23, 2013. Fourteen new joiners to the 128-giant-panda-family at the base were shown to the public on Monday, according to local media. (Photo by Reuters/China Daily)

Cheng Chen (R), a 27-year-old worker at a state-owned enterprise, poses for a photograph with his nephew who is wearing his home-made Iron Man armour, in Xuzhou, Jiangsu province April 13, 2015. It cost Cheng about 500 yuan ($81 USD) to make the armour, which weighs about 4 kilograms, with plastic boards and LED lights, local media reported. (Photo by Reuters/Stringer)

In this photograph taken on January 19, 2012, Indonesian schoolchildren hold on to iron cables as they cross a nearly-collapsed suspension bridge at Sanghiang Tanjung village in Indonesia's Banten province to reach their school. (Photo by Kris Aria/AFP Photo)

The faces of war have been brought back to life after a series of World War One photographs were expertly colourised. The black and white snaps were painstakingly restored and colourised by photographer Mario Unger (53) from Rotenturm, Austria. Here: One image shows an unidentified American soldier posing with a pistol, helmet, and Iron Cross medal taken from a German soldier, 1918. (Photo by Mario Unger/Mediadrumworld)

Marco Antonio Eguchi of Brazil gets bucked off of Bottoms Up in the first round of the PBR Frontier Communications Iron Cowboy at AT& T Stadium on February 18, 2017 in Arlington, Texas. (Photo by Tom Pennington/Getty Images)

A baby giant panda plays at Chengdu Research Base of Giant Panda Breeding in Chengdu, Sichuan province, China, January 22, 2017. (Photo by Jason Lee/Reuters)

19 giant panda cubs, all born this year, meet the public at the Shenshuping Base of the China Conservation and Research Centre for the Giant Panda on October 13, 2017 in Ngawa Tibetan and Qiang Autonomous Prefecture, China. So far China Conservation and Research Centre for the Giant Panda has successfully bred 42 giant pandas this year. (Photo by VCG/VCG via Getty Images)