A visitor kneels on the 180-meter-high and 300 meter-long glass-bottomed suspension bridge at the Shiniuzhai National Geopark in Pingjiang county, in central China's Hunan province, 24 September 2015. (Photo by Jiao Zi/Imaginechina via AFP Photo)

(L-R) US singer Halsey, models Gigi Hadid and Bella Hadid and Bebe Rexha (bottom L) clap during 2019 MTV Video Music Awards at the Prudential Center in Newark, New Jersey on August 26, 2019. (Photo by Lucas Jackson/Reuters)

A couple stands next to a poster depicting Dutch politician Geert Wilders and Russian President Vladimir Putin kissing, at a metro station in Amsterdam April 3, 2016. (Photo by Cris Toala Olivares/Reuters)

Members of the LGBT community kiss during a Kissathon to celebrate International Day Against Homophobia, outside Bellas Artes museum in Mexico City, Mexico, May 17, 2016. (Photo by Edgard Garrido/Reuters)

Two women wearing bejewelled bras kiss during the annual Sydney Gay and Lesbian Mardi Gras festival in Sydney, Australia March 4, 2017. (Photo by Jason Reed/Reuters)

Marchers kiss as they walk down 5th Avenue as they part in the 2019 World Pride NYC and Stonewall 50th LGBTQ Pride Parade in New York, U.S., June 30, 2019. (Photo by Lucas Jackson/Reuters)

Cast member George Clooney kisses the hand of his wife Amal Clooney on the red carpet for the screening of ”Jay Kelly” on August 28, 2025. (Photo by Yara Nardi/Reuters)

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)