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 man impersonating Kim Jong-un gestures during the athletics at the Rio 2016 Olympic Games at the Olympic Stadium in Rio de Janeiro on August 18, 2016. (Photo by Johannes Eisele/AFP Photo)

A picture taken on July 14, 2014 from a Boeing C135 refueling tanker shows two French Rafale fighter planes, flying over the French capital during the annual Bastille Day military parade on the Champs-Elysees in Paris. France has issued an unprecedented invitation to all 72 countries involved in World War I to take part in its annual Bastille Day military parade. (Photo by Franck Pennant/AFP Photo)

An Afghan girl harvests Cotton buds at a field on the outskirts of Balkh province, Afghanistan, November 15, 2014. (Photo by Sayed Mustafa/EPA)

A camel yawns as a tourist checks images on her camera following a ride on a camel safari alongside the Pacific Ocean on Lighthouse Beach, north of Sydney, December 4, 2014. For 25 years camel rides on this beach have given visitors to Australia's holiday coast a rare experience available only in a handful of locations in the country. Australia's long history with the “ships of the desert” goes back to the 1800s when they were imported from Afghanistan and India for use as transportation across Australia's vast deserts before being released into the wild following their replacement by motorised transport. (Photo by Jason Reed/Reuters)

Soldiers take part in a drill during a heavy snow in Heihe, Heilongjiang province, February 26, 2014. (Photo by Reuters/China Daily)

A cadet lies on the grass after collapsing during a promotion ceremony at a police school in Bogota December 7, 2012. (Photo by John Vizcaino/Reuters)

A delegate dressed in a furry Lion costume walks across a Zebra crossing to the convention centre at the Eurofurence convention in Berlin on August 17, 2017. Some 2700 delegates are taking part in the 3-day-long Eurofurence in the German capital, the worlds oldest active Furry-convention for people dressing up in furry costumes. (Photo by Odd Andersen/AFP Photo)