Beneath the Swedish capital lies an intricate web of underground train lines. More than 90 of the 100 stations in the 110km tunnel system, sometimes referred to as “the world’s longest art gallery”, have been decorated with paintings, installations, mosaics and sculptures by 150 artists since the 1950s. After spending a couple of weeks exploring arctic Norway and Sweden, London-based travel photographer Conor MacNeill headed underground to capture images of the metro stations. Here: A rainbow arcs over a girl on the platform of Stadion station. (Photo by Conor MacNeill/The Observer)

A woman dives and pretends to ride a bike in Underwater Park in Pula, Croatia, August 1, 2017. (Photo by Antonio Bronic/Reuters)

The snitch runner takes the broom from between the legs of a Werewolves of London quidditch player during the Crumpet Cup quidditch tournament on Clapham Common on February 18, 2017 in London, England. (Photo by Jack Taylor/Getty Images)

Some are in it just for the money, others to help buy a meal. Then there are those who trade for fun or to spend time among friends. Millions of investors – pensioners, security guards, high-school students – dominate China's stock markets, conducting about 80 percent of all trades. Retirees gather in brokerage houses dotted around China also to enjoy some company and savour the air conditioning on hot days. Some start as young as 13, trading from home with an eye on future careers in finance. Winning isn't guaranteed. This year, among the most turbulent in China's financial history, its stock markets more than doubled in the six months to May, only to crash amid concerns that growth in the country, which makes everything from cars to steel, is slowing faster than previously thought. (Photo by Aly Song/Reuters)

A camel rests at a fuel station in the Judean desert near the West Bank city of Jericho January 11, 2015. Reuters photographers from Mali to Mexico have shot a series of pictures of fuel stations. Whether it is plastic bottles by the roadside in Malaysia or a futuristic forecourt in Los Angeles, fuel stations help define our world. Oil prices steadied above $48 a barrel on Tuesday, recovering from earlier losses as the dollar weakened against the euro. Oil prices have dropped nearly 60 percent since peaking in June 2014 on ample global supplies from the U.S. shale oil boom and a decision by OPEC to keep its production quotas unchanged. (Photo by Baz Ratner/Reuters)

An adorable 11-week old lion cub named Karis had a very exciting day playing in a pile of autumn leaves that her keeper swept into her enclosure at the Blair Drummond Safari and Adventure Park in Scotland. This proved to be a very wise decision on her keeper’s part, as she seems to have had the time of her life frolicking around in the pile of leaves

Space shuttle Atlantis (R) remains docked to the International Space Station photographed by NASA astronaut Ronald Garan during a planned six-and-a-half-hour spacewalk July 12, 2011 in space. Space shuttle Atlantis has embarked on a 12-day mission to the International Space Station where it will deliver the Raffaello multi-purpose logistics module packed with supplies and spare parts. This was the final mission of the space shuttle program, which began on April 12, 1981 with the launch of Colombia. (Photo by NASA via Getty Images)