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. “They’d been famous among the world of photographers for a long time”, he says. “I wanted to see them for myself and take my own approach on the subject. I shot late into the night – I just keep getting carried away exploring”. Here: Painted blue vines climbing up a white cave in the T-Centralen station. (Photo by Conor MacNeill/The Observer)





Solna Centrum station on the blue line (T11). (Photo by Conor MacNeill/The Observer)





Kungsträdgården metro station on the green line of the Stockholm T-Bana. (Photo by Conor MacNeill/The Observer)





A rainbow arcs over a girl on the platform of Stadion station. (Photo by Conor MacNeill/The Observer)





Skarpnäck station. The granite seats are reminiscent of Stonehenge. (Photo by Conor MacNeill/The Observer)





Pipes come out of the ceiling at Universitetet. (Photo by Conor MacNeill/The Observer)





Akalla station, on the blue line. (Photo by Conor MacNeill/The Observer)





A woman stands on the platform of Tekniska Högskolan as a train rushes by. (Photo by Conor MacNeill/The Observer)





The escalators at Solna Centrum T-bana. (Photo by Conor MacNeill/The Observer)





A dodecahedron suspended from the ceiling at Tekniska Högskolan. (Photo by Conor MacNeill/The Observer)





Stripes on the platform of Duvbo station. (Photo by Conor MacNeill/The Observer)





Rådhuset (Court House) station, on the blue line. (Photo by Conor MacNeill/The Observer)





Huvudsta station. (Photo by Conor MacNeill/The Observer)