A man takes a picture of models as they pose next to Cosmis Racing Wheels products during the 2016 Moscow International Auto Salon in Moscow, Russia, August 26, 2016. (Photo by Sergei Karpukhin/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)

This 2014 series Shanghai Tian Wa saw Chinese photographer Liu Tao train his lens on two distinct districts in Shanghai. Here: “Shanghai Tian Wai №26, 2014”. (Photo by Liu Tao/The Guardian)

A horse smiles at the camera. See the beautiful images of horses gleefully playing in Iceland mountain ranges. The horses have been spotted smiling and cuddling in remote locations across the nation. (Photo by Bragi J. Ingibergsson/Caters News)

A grizzly bear eats a frozen fruits during a hot summer day at Rio de Janeiro's zoo January 13, 2015. According to a local climate institute, temperatures in Rio de Janeiro on Tuesday rose up to 34 degrees Celsius (93.2 degrees Fahrenheit). (Photo by Sergio Moraes/Reuters)

A giant storm cloud can be seen in the sky above swimmers near Mollymook Beach, south of Sydney, March 5, 2014. (Photo by David Gray/Reuters)

Charlotte Bridgeman poses for a series of triptych portraits during New York Fashion Week February 6, 2014. Bridgeman, from Australia, is attending her second fashion week. (Photo by Carlo Allegri/Reuters)

A steam traction engine with a broken rear axle in Pall Mall, London. (Photo by Topical Press Agency/Getty Images). November 1923