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 young girl takes selfie with Easter rabbit sculpture during the Easter eggs (Pysanka) and rabbit exhibition in front of St. Sophia Cathedral in Kiev, Ukraine, 05 April 2018. Ukrainians will mark Orthodox Easter on 08 April 2018, according to Julian calendar. (Photo by Sergey Dolzhenko/EPA/EFE/Rex Features/Shutterstock)

Kendall Jenner attends the screening of “Girls Of The Sun (Les Filles Du Soleil)” during the 71st annual Cannes Film Festival at Palais des Festivals on May 12, 2018 in Cannes, France. (Photo by Stephane Cardinale/Corbis via Getty Images)

An Indian girl cries as a medical worker collect her swab sample for COVID-19 test at a rural health center in Bagli, outskirts of Dharmsala, India, Monday, September 7, 2020. India's coronavirus cases are now the second-highest in the world and only behind the United States. (Photo by Ashwini Bhatia/AP Photo)

Two girls dressed up for a night out in Newcastle, United Kingdom on November 01, 2020 – just hours after Boris Johnson's announcement. Johnson says the new measures will begin on Thursday and last until second of December. (Photo by North News and Pictures/The Sun)

A girl dives under a wave at Bondi Beach as temperatures reached 29 degrees celsius on December 17, 2020 in Sydney, Australia. The Bureau of Meteorology predicted the arrival of thunderstorms and showers later today with a southerly change bringing possible severe storms around the Sydney region. (Photo by Mark Evans/Getty Images)