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)

Dancers perform during the annual Tbilisoba festival, celebrating Tbilisi City Day in Tbilisi, Georgia, October 17, 2015. Tbilisoba is an annual October festival, celebrating the diversity and history of Tbilisi, the capital of Georgia. (Photo by David Mdzinarishvili/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)

This image released by Esquire shows actress Penelope Cruz on the November 2014 cover of “Esquire” magazine. The magazine has named Cruz The Sexiest Woman Alive for 2014. (Photo by AP Photo/Esquire)

Space Shuttle Discovery is towed from the shuttle landing facility to the orbiter processing facility at Kennedy Space Center on April 20, 2010 in Cape Canaveral, Florida. Discovery's landing attempts at KSC were scrubbed yesterday due to unacceptable weather conditions. Discovery is returning from a successful mission to the International Space Station. (Photo by Matt Stroshane/Getty Images). CAPE CANAVERAL, FL – APRIL 20 2010