In this September 1, 2015 photo, street artists Jenaro de Rosenzweig, left, and Alejandro Revilla pose for a portrait behind a restaurant's window covered with a mural by artist Francisco Munoz, signed with his artist's name below, in the Roma Norte neighborhood of Mexico City. Rosenzweig and Revilla founded the “Street Art Chilango” cooperative in March 2013, which is filling neighborhoods with public art by local street artists. (Photo by Rebecca Blackwell/AP Photo)

This undated photo provided by NOAA in May 2018 shows aurora australis near the South Pole Atmospheric Research Observatory in Antarctica. When a hole in the ozone formed over Antarctica, countries around the world in 1987 agreed to phase out several types of ozone-depleting chemicals called chlorofluorocarbons (CFCs). Production was banned, emissions fell and the hole shriveled. But according to a study released on Wednesday, May 16, 2018, scientists say since 2013, there’s more of a banned CFC going into the atmosphere. (Photo by Patrick Cullis/NOAA via AP Photo)

A woman carries her child as she watches Mount Sinabung volcano spewing thick volcanic ash, as seen from Karo on July 21, 2017. Sinabung roared back to life in 2010 for the first time in 400 years, after another period of inactivity it erupted once more in 2013, and has remained highly active since. (Photo by Gatha Ginting/AFP Photo)

A student falls asleep as she holds a book containing a portrait of China's late chairman Mao Zedong during a lesson at the Democracy Elementary and Middle School in Sitong town, Henan province December 3, 2013. In a remote part of central China, the day starts at the Democracy Elementary and Middle School with a pre-dawn jog, some revolutionary songs and then an activity long since forgotten at other schools: reciting quotations from Mao Zedong's famed “Little Red Book”. While the ruling Communist Party that Mao led continues to hold him in esteem as the leader of the Communist Revolution, his radical policies and teachings have been largely shelved since his death in 1976 in favour of a pro-market approach that has turned China from a backwater into the world's second biggest economy. The 120th anniversary of Mao's birth is on December 26, 2013. (Photo by Carlos Barria/Reuters)

In celebration of the Spring Solstice 2013 and in conjunction with the release of Dreamworks’ 3D animation The Croods – a family animation centered around the first ever pre historic road trip – a giant monument was built at Stonehenge at sunrise on Tuesday March 19, 2013. This marks the first time a modern structure has Ever been allowed on this historic site. (Photo by Flashforwardpublicity.com)

Wildlife are hunted down for consumption or for sale in the India eastern state of Nagaland. Hunters can make a good living, with some bred for food or to be sold as pets. These baby parrots, photographed by Caisii Mao via Sipa USA, are seen after they were caught and preserved by a local hunter and for sale at a private residence in Dimapur, India north eastern state of Nagaland on Wednesday, July 24, 2013. (Photo by Caisii Mao/NurPhoto/Sipa USA)

“These are the mind-blowing artworks of one professor who has dedicated his professional life to studying and generating a series of dizzying optical illusions. Professor Akiyoshi Kitaoka, from Ritsumseikan University, in Kyoto, Japan, has spent more than a decade creating his collecting of stomach-churning works. His designs have been used by the likes of Lady Gaga, who ran the Kitaokas work, entitled Gangaze, as the CD cover for her album Art Pop, in 2013”. – Caters News. (Photo by Akiyoshi Kitaoka/Caters News)

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)