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 British Airways passenger plane flies in front of the moon above London, Britain, May 3, 2018. (Photo by Toby Melville/Reuters)

A cave diver in Anhumas Abyss, Bonito, Brazil. (Photo by Marcio Cabral/Epson International Pano Awards 2018)

In this June 29, 2018 photo, a wild horse shakes off dust near a watering hole outside Salt Lake City. Harsh drought conditions in parts of the American West are pushing wild horses to the brink and forcing extreme measures to protect them. (Photo by Rick Bowmer/AP Photo)

A diesel locomotive has ended up in the river Venoge on March 8, 2013 near Penthalaz, Western Switzerland. The freight locomotive derailed near Cossonez railway station with its driver slightly injured. (Photo by Fabrice Coffrini/AFP Photo)

A fado singer smokes a cigarrette outside a fado house at the Alfama neighborhood in Lisbon on May 8, 2019. From fado sounds to Cape Verde mornas or bossa nova: the Lisbon nights, where musicians from all over the world meet, have largely inspired Madonna's new album, who has been in the Portuguese capital since 2017. (Photo by Patrícia de Melo Moreira/AFP Photo)

American singer Ciara, Russian supermodel Natasha Poly and American media personality Olivia Culpo attend the amfAR After Party at Hotel du Cap-Eden-Roc on May 26, 2022 in Cap d'Antibes, France. (Photo by Jacopo M. Raule/Getty Images for Revolve)

Hungary's athlete Anna Toth receives help after a fall in the women's 100m hurdles semifinal during the European Athletics Championships at the Olympic stadium in Rome on June 8, 2024. (Photo by Anne-Christine Poujoulat/AFP Photo)