People look at sharks from an underwater room structure installed in the Aquarium of Paris, France, March 14, 2016. Airbnb and the Aquarium of Paris offer contest winners a night underwater sleeping with sharks and create a research platform for “misunderstood” shark species. (Photo by Charles Platiau/Reuters)

Harry Potter fan Emil Valkov, 7, from Bulgaria, who travelled to Britain with his family to attend the event for his older sister's birthday, poses for a photo at “Platform 9 3/4” during Back to Hogwarts Day at Kings Cross Station in London, Britain on September 1, 2023. (Photo by Hollie Adams/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)

Robbie Lee of Team Great Britain competes in the Men's 10m Platform Preliminaries on day 23 of the Singapore 2025 World Aquatics Championships at OCBC Aquatic Centre on August 02, 2025 in Singapore. (Photo by Adam Pretty/Getty Images)

Hugo Gonzalez of Lake Worth works to put final strokes on his rendition of a Raksha demon. (Photo by Thomas Cordy/The Palm Beach Post)

The “EMIEW3” robot (R) demonstrates communicating with a visitor during a press preview in Tokyo on April 8, 2016. Japanese electronics giant Hitachi unveiled its humanoid customer service and guidance robot “EMIEW3” and “remote brain” robotics IT platform. (Photo by Toshifumi Kitamura/AFP Photo)