Participants climb over a wall at the “Tough Mudder” endurance event series in Arnsberg September 6, 2014. Competitors who took part in the endurance event saw themselves having to overcome various military style obstacles. (Photo by Ina Fassbender/Reuters)

Tourists pose for a selfie in an old American car in front of a wall bearing a graffiti of the Committees for the Defense of the Revolution (CDR) in Havana, on September 27, 2023. September 28 marks the 63th anniversary of the Committees for the Defense of the Revolution (CDR), the so-called “eyes and ears of the Revolution” created by the late Cuban leader Fidel Castro. (Photo by Yamil Lage/AFP Photo)

Soap Bubble Structures by Kym Cox. Bubbles optimise space and minimise their surface area for a given volume of air. This phenomenon makes them a useful tool in many areas of research, in particular, materials science and “packing” – how things fit together. Bubble walls drain under gravity, thin at the top, thick at the bottom, which interferes with travelling lightwaves to create bands of colour. Black spots show the wall is too thin for interference colours, indicating the bubble is about to burst. (Photo by Kym Cox/2019 Science Photographer of the Year/RPS)

A woman walks past graffiti on a wall in the Williamsburg neighborhood of the borough of Brooklyn, in New York, September 16, 2014. The picture was taken through car window with raindrops. (Photo by Shannon Stapleton/Reuters)

A newborn baby pangolin climbs the walls of a cage in Bangkok, Thailand April 20, 2011. The Thai custom office showed 175 pangolins they found hidden in a truck heading into Bangkok. (Photo by Damir Sagolj/Reuters)

A hostess sits at a restaurant with paintings depicting Thailand's King Bhumibol Adulyadej hanging on a wall in Bangkok, Thailand, June 6, 2016. (Photo by Athit Perawongmetha/Reuters)

Police officers detain a man during a gathering in memory of Russian opposition leader Alexei Navalny near the Wall of Grief monument to the victims of political repressions in Moscow, Russia on February 17, 2024. (Photo by Reuters/Stringer)

Reverend Peter Wall blesses a hamster during “The Blessing of Animals” at St. James Cathedral in Toronto, Ontario, Canada on September 30, 2023. (Photo by Mert Alper Dervis/Anadolu Agency via Getty Images)