After the success of their Superman series in 2013, the Canadian Mint debuted a new set of coins honouring the Man of Steel at this year's Fan Expo in Toronto. The collection is made up of three silver coins worth $10, $15 and $20, and a gold coin worth $100. Photo: Close-up of the $10 silver coin in the new Superman series from the Royal Canadian Mint. (Photo by The Canadian Press)

Axel, a research prototype rover for exploring the Moon, Mars and other planets, is remotely driven over rocks as engineers from Jet Propulsion (JPL) and grad students from Caltech (California Institute of Technology) demonstrate its mobile over the steep and rocky grounds of the JPL Mars Yard on January 14, 2009 in Pasadena, California. The rover is capable of descending cliffs or into craters and returning by a cable tethered to its starting point. Development of the Axel rover is a point effort funded by NASA Exploration Systems Mission Directorate (ESMD) and lead by Principal Investigator Issa Newnas and Co-Investigator and Caltech professor of mechanical engineering bio engineering Joel Burdick. (Photo by David McNew/Getty Images)

Figures from Antony Gormley's “Field For The British Isles” adorns an exhibition space in St Helen's College in the town of it's creation 15 years ago, June 23, 2008, St Helens, England. The installation of over 40,000 clay figures has returned to the place where it was made by local people from local clay. Artist Antony Gormley describes his creation as “25 tons of clay energised by fire, sensitised by touch and made conscious by being given eyes ... a field of gazes which looks at the observer making him or her its subject”. (Photo by Christopher Furlong/Getty Images)

A stork-billed kingfisher (Pelargopsis capensis) is seen perched on a tree during monsoon rain on July 25, 2016 in Bintan, Indonesia. The stork-billed kingfisher is a tree species which is widely but sparsely distributed in the tropical Indian subcontinent and Southeast Asia, from India to Indonesia. This kingfisher is resident throughout its range. It is very large, measuring 35 to 38 cm (14 to 15 in) in length. The adult has a green back, blue wings and tail, and grey head. (Photo by Sijori Images/Barcroft Images)

Autos sit on top of each other in a washed out section of Dog Track Road in the Millview community as Gulf Coast residents continue cleaning up from damage caused by torrential rains in Pensacola, Fla., Thursday, May 1, 2014. The National Weather Service, estimated 15-20 inches of rain has fallen in the Pensacola area in the past 2 days. (Photo by G. M. Andrews/AP Photo)

Hindu holy man, or sadhu, applies paint to his forehead at his ashram on the premises of Pashupatinath Temple in Kathmandu February 15, 2015. Hindu holy men from Nepal and India come to this temple to take part in the Maha Shivaratri festival. Celebrated by Hindu devotees all over the world, Shivaratri is dedicated to Lord Shiva, and holy men mark the occasion by praying, smoking marijuana or smearing their bodies with ashes. (Photo by Navesh Chitrakar/Reuters)

A girl carries fire wood collected from flood waters in the flood affected Morigaon district of Assam state, India, 25 July 2016. Over half a million people of 15 districts in Assam state have been affected by the current wave of floods. According to the media reports more than 70 relief camps have been set up in the affected districts to provide shelter to the flood affected people. (Photo by EPA/Stringer)

An Indian farmer from Tamil Nadu state wearing a necklace of human skulls representing suicides by agricultural workers takes part in a protest with other farmers in New Delhi on March 15, 2017. Tamil Nadu state farmers protested to demand a profitable price for their agricultral products, and called for the formation of management committee for solving Cauvery river water disputes. More than 200 farmers have committed suicide in Tamil Nadu in recent months following crop failure due to poor rainfall and inadequate water for irrigation. (Photo by Prakash Singh/AFP Photo)