Window washers from the American National Skyline company (from left to right in the image below: Jordan Emerson, Steve Oszaniec and Danny Oszaniec) suit up as Marvel Comics superheroes to pleasantly surprise the children (who are patients) and their families inside as the dressed up crew cleans the outside of the windows at Le Bonheur Children’s Hospital in Memphis

A resident looks at a wildfire in Vina del Mar, Chile, March 12, 2017. Forest fires are a regular feature of Chile's hot, arid summers, but a nearly decade-long drought combined with historically high temperatures have created tinder-like conditions in the nation's central regions. (Photo by Rodrigo Garrido/Reuters)

Two rainbows emerge from a black storm above the mountains, on August 19, 2014, in Kingman, Arizona. Double tornadoes, lightning storms and rotating supercells – this is what it's like to chase storms for a year. These dramatic images show apocalyptic weather throughout 2014 from a lightning storm to a pair of rainbows. Roger Hill, 57, has been chasing storms in the United States for thirty years and runs a tour operation with his wife Caryn. His favourite photograph of the year was also one of the most difficult to get – as two violent tornadoes tore through Pilger, Nebraska on June 16. The spiraling winds killed a five-year-old girl and injured at least 19 others, and as Roger tried to get the perfect shot debris began to rain down on his car. (Photo by Roger Hill/Barcroft Media)

Soldiers stand in front of a floral decoration during celebrations to commemorate the 70th anniversary of the establishment of the Vietnam People's Army at the National Convention Center in Hanoi December 20, 2014. The Vietnam People's Army was founded on December 22, 1944 and led by General Vo Nguyen Giap in Cao Bang province, initially with only 34 members. (Photo by Reuters/Kham)

People remove mud and rocks from their house after a massive landslide in Chosica, March 24, 2015. Seven people were killed and more were feared dead in Peru after a massive landslide buried parts of a town amid heavy rains, authorities said on Tuesday. Six were missing and 25 injured in the disaster in Chosica, some 30 kilometers (18.6 miles) east of Lima, said Alfredo Murgueytio, the head of the National Civil Defense Institute, Indeci. (Photo by Mariana Bazo/Reuters)

A Waura Indian woman watches the activities of this year's “quarup”, a ritual held over several days to honour in death a person of great importance to them, in Xingu National Park, Mato Grosso State, August 24, 2013. This year the Waura tribe is honouring their late cacique (chief) Atamai, who died in 2012 and helped created the Xingu Park, and his important contribution in facilitating communication between white Brazilians and Indians. (Photo by Ueslei Marcelino/Reuters)

An arctic tern feeds its chick on the Farne Islands off the Northumberland coast, northern England July 8, 2013. The Farne Islands, which lie off the coast of northeast England, are home to a huge array of wildlife. The islands are owned and protected by the British conservation charity, the National Trust, which says they host some 23 species of seabird, as well as a substantial colony of grey seals, who come to have their pups there in the autumn. Every five years the National Trust carries out a census of the islands' population of puffins, and this year's survey showed there were almost 40,000 nesting pairs on the islands – an 8 percent rise from 2008. (Photo by Nigel Roddis/Reuters)

“A fter the former Soviet Union conducted its first nuclear test in August 1949, the US reevaluated its postwar defense policies. With the US monopoly on atomic weapons broken, military and political leaders chose to diversify the American stockpile by developing thermonuclear and tactical nuclear weapons. One of the more interesting concepts to come out of this period was atomic artillery, which was successfully tested at the Nevada Proving Grounds (now the Nevada Test Site) in May 1953”. – Alan Carr. Photo: Atomic Annie at work during the Upshot-Knothole test series, 1953. (Photo by Los Alamos National Laboratory/US Army)