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 girl washes the body paint off her arm on the shore of Lake Balaton during the coinciding Strand Festival and B.My.Lake Festival in Zamardi, 110 kms southwest of Budapest, Hungary, 24 August 2016. (Photo by Zoltan Balogh/EPA)

A girl poses at an entrance of her house next to a bomb dropped by the U.S. Air Force planes during the Vietnam War, in the village of Ban Napia in Xieng Khouang province, Laos September 3, 2016. From 1964 to 1973, U.S. warplanes dropped more than 270 million cluster munitions on Laos, one-third of which did not explode, according to the Lao National Regulatory Authority. (Photo by Jorge Silva/Reuters)

A school girl reacts as a health worker inoculates her with the dose of Pfizer-BioNTech vaccine against the Covid-19 coronavirus for the 12-15 years age group at an educational institution in Colombo on January 7, 2022. (Photo by Ishara S. Kodikara/AFP Photo)

Girls lead a gaggle of geese, backdropped by a banner against the war in Ukraine, during a Saint Martin's Day procession next to Charles Bridge in Prague, Czech Republic, Friday, November 11, 2022. Saint Martin's day marks the end of the harvest season as well as the start of winter. (Photo by Vadim Ghirda/AP Photo)

Teenage girls at a drinking fountain in Hyde Park in Central London on August 9, 2022 after weeks with no significant rain and unprecedented high temperatures. Many parts of southern England and Wales are facing drought conditions and preparing for emergency water measures. (Photo by Sarah Lee/The Guardian)

A girl walks past destroyed houses at Basara refugee camp in Sittwe on May 16, 2023, after cyclone Mocha made a landfall. The death toll in cyclone-hit Myanmar's Rakhine state rose to at least 41 on May 16, 2023, local leaders told AFP. (Photo by Sai Aung Main/AFP Photo)

Iranian school girls show their hands with pro-government slogans and an anti-Israeli slogan which reads in Farsi: “Death to Israel”, during a rally in front of the former U.S. Embassy in Tehran, Iran, marking 44th anniversary of the seizure of the embassy by militant Iranian students, Saturday, November 4, 2023. (Photo by Vahid Salemi/AP Photo)