Germany fans cheer after the 2-0 goal for Germany during the UEFA Euro 2024 football match between Germany and Hungary at the public football viewing area in Berlin, Germany on June 19, 2024. (Photo by Jörg Carstensen/AFP Photo)

Roma's Gianluca Mancini scores his team's goal in the 1-0 Rome derby victory over Lazio at Stadio Olimpico in Rome, Italy on April 6, 2024. (Photo by Alberto Lingria/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)

Participants kiss on a platform as they take part in the annual event “No Trousers Tube Ride” in London, Sunday, January 8, 2023. The No Trousers Tube Ride returns to London, the first time the event had taken place since January 2020, due to Covid. (Photo by Kin Cheung/AP Photo)

To mark World Water Day, on March 22nd Solidarités International and its agency BDDP Unlimited will roll out a campaign to build awareness of the scourge of undrinkable water.