Students wearing masks rest amid the coronavirus disease (COVID-19) pandemic in Seoul, South Korea, August 25, 2020. (Photo by Kim Hong-Ji/Reuters)

Filipino students performs during the parade at the 125th Philippine’s Independence Day at Dubai World Trade Centre on June 10, 2023. (Photo by Leslie Pableo for The National)

People attend the New Year's eve gala of youth and students at Kim Il Sung Square in Pyongyang, North Korea Sunday, December 31, 2023. (Photo by Jon Chol Jin/AP Photo)

College students dress in the guise of Hindu deities Krishna and Radha, ahead of Janmashtami festival, in Chennai on August 23, 2024. (Photo by R.Satish Babu/AFP Photo)

A student poses with her painted face, ahead of New Year celebrations at a college in Chennai on December 28, 2024. (Photo by R. Satish Babu/AFP Photo)

Students participate in a commemorative march near the Arch of Triumph in Pyongyang on April 25, 2025, to mark the 93rd anniversary of the Korean People's Revolutionary Army. (Photo by Kim Won Jin/AFP Photo)

A sculptural artwork depicting former Chilean dictator Augusto Pinochet and headless presidents shot by a hooded high school student (not pictured) is seen at the Contemporary Art Museum in Santiago, December 2, 2014. The artwork, part of the “El ladrillo angular” (The angular brick) exhibition, portrays a student fighting against the ongoing continuity of dictatorship because of a political and economic system which has been impossible to destroy, according to “Papas Fritas” the artwork's creator. (Photo by Ivan Alvarado/Reuters)

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)