Syrian boys play with plastic guns on the first day of the Muslim religious festival of Eid al-Adha in al-Dana in Syria's rebel-controlled Idlib region, near the border with Turkey, on August 11, 2019. Muslims across the world are celebrating the first day of the Feast of Sacrifice, which marks the end of the hajj pilgrimage to Mecca and commemorates prophet Abraham's sacrifice of a lamb after God spared Ishmael, his son. (Photo by Aaref Watad/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)

Young conductors stand in line during the steam locomotive presentation at the Kyiv Children's Railway Station on July 3, 2022 in Kyiv, Ukraine. According to the railway's operators, the Gr-336 locomotive was built in Germany in 1951 and brought to Kyiv as part of reparations in the wake of World War II. (Photo by Alexey Furman/Getty Images)

Iran's Hanieh Rajabi performs during the women's Daoshu competition at the 13th Wushu World Championships in Jakarta, Indonesia, Monday, November 16, 2015. (Photo by Tatan Syuflana/AP Photo)

A masked tourist poses for a souvenir photo next to a graffiti titled “Mobile World Virus” depicting “La Gioconda”, aka Mona Lisa, with a mobile phone and a medical mask, by urban artist TVBoy, close to the Sant Jaume square in Barcelona, Spain, 09 March 2020. Barcelona's Deputy Mayor and two town councillors are in quarantine after they were in contact with a City Hall's worker who was tested positive for the COVID-19 coronavirus. (Photo by Quique Garcia/EPA/EFE)

A man pours fake fuel on the face of a protester as they perform at a demonstration against the fossil fuel industry during the UN Climate Change Conference (COP26), in Glasgow, Scotland, Britain, November 7, 2021. (Photo by Yves Herman/Reuters)

Linda Cerruti, Lucrezia Ruggiero, Marta Iacoacci, Isotta Sportelli, Sofia Mastroianni, Giulia Vernice, Enrica Piccoli and Francesca Zunino of Team Italy compete in the Mixed Team Technical Final on day five of the Doha 2024 World Aquatics Championships at Aspire Dome on February 06, 2024 in Doha, Qatar. (Photo by Maddie Meyer/Getty Images)

People dressed as zombies take part in a “Zombie Walk” parade in Athens, Greece, February 25, 2017. (Photo by Michalis Karagiannis/Reuters)