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)

The sun rises through the thick fog that covers the city of Frankfurt, Germany, Friday, November 12, 2021. (Photo by Michael Probst/AP Photo)

An old car passes by while dark clouds are seen due to the tropical storm Idalia in Havana, on August 28, 2023. (Photo by Yamil Lage/AFP Photo)

Women clash with police officers behind riot shields during a protest in support of Victoria Salazar, a Salvadoran woman who died after a Mexican female police officer was seen in a video kneeling on her back, in Mexico City, Mexico on April 2, 2021. (Photo by Raquel Cunha/Reuters)

A visitor poses with artist Joyce Pensato's artwork “Mickey for Micky” at the Frieze Art Fair in London, October 14, 2014. (Photo by Luke MacGregor/Reuters)

The work entitled “Trip 1, Trip II, Trip III” by April Pine is pictured before dawn at Sculpture By The Sea at Bondi Beach on October 19, 2017 in Sydney, Australia. This year the outdoor exhibition celebrates its 21st birthday with 104 exhibiting artists from Australia and around the world and runs from the 19th October-5th November 2017. (Photo by Brook Mitchell/Getty Images)

Aviator Frantisek Hadrava moves Vampira, an ultralight plane based on the U.S.-design of light planes called Mini-Max, out of a garage in the village of Zdikov, Czech Republic, August 23, 2016. Frantisek thought driving to work for 14 minutes was too much, so he built an plane to cut the commute by half. (Photo by David W. Cerny/Reuters)