A glass skywalk in Wanyuan, Sichuan province, built along the side of a cliff, is the highest such skywalk anywhere in China on January 31, 2017. Some visitors have been proven to be terrified by the experience had to brace against the wall in fear. (Photo by Chinanew.com/AsiaWire)

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)

A migrant labourer gets a shave besides a closed shop in a market area in the old quarters of the walled city, Delhi during an ongoing state-wide weekend curfew imposed by the directive of the Delhi government to curb the spread of the Covid-19 coronavirus in New Delhi on January 9, 2022. (Photo by Money Sharma/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)

Human canvases modelling world famous artworks including Van Gogh's Sunflowers and Edvard Munch's The Scream take to the streets of London in a bid to mend Britain's disconnect with art on September 25, 2017. Award winning body paint artist Sarah Attwell was commissioned by online art platform Rise Art to show that great art is for everybody, following research that revealed 1 in 6 Brits have never set foot in an art gallery. (Photo by Imagewise Ltd/Rex Features/Shutterstock)

A man watches as high surf crashes into the wall and spills onto Channel Drive in Montecito, Calif., January 7, 2016. Bacteria levels can increase significantly during and after rainstorms as contaminants in the runoff enter the ocean via storm drains, creeks and rivers. (Photo by Mike Eliason/AP Photo)

A man looks at a mural painted on the walls of houses in Zaraeeb, created by French-Tunisian artist El Seed, in the shanty area known also as Zabaleen or “Garbage City” on the Mokattam Hills in eastern Cairo, Egypt, April 4, 2016. (Photo by Amr Abdallah Dalsh/Reuters)

A woman looks at a mural by South African artist FAITH 47 which decorates a wall in the village of Erriadh, on the Tunisian island of Djerba, on August 8, 2014, as part of the artistic project “Djerbahood”. Artists from 34 diffrents nationalities were invited by France-based Tunisian artist Mehdi Ben Cheikh to take part in an initiative to turn Djerba's Erriadh district into an “open sky museum”. (Photo by Joel Saget/AFP Photo)