A walker has left a handprint on a snow- covered tree trunk on Grosser Feldberg mountain in the Taunus mountain range, Germany, 16 January 2017. (Photo by Frank Rumpenhorst/DPA)

With its huge eyes, comical name and diminutive size, Mark R. Smith’s image of a baby Hawaiian bobtail squid can’t help but raise a smile. A curiously endearing creature, the cephalopod is just 1.5cm across, its mantle cavity bearing more than a passing resemblance to a rather natty shower cap. But it is also a beautiful example of symbiosis – nature’s version of “I’ll scratch your back if you scratch mine” – for on the underside of the squid is a light organ which houses bioluminescent bacteria. The squid offers the bacteria protection and food, while the bacteria emit a glow – a handy trait that the squid uses to offset its silhouette, helping it to evade predators in the depths below. Mark R. Smith’s entry combines several images of a Hawaiian bobtail squid with different focus lengths to create a final picture with greater depth of field than normal. (Photo by Mark R. Smith/Wellcome Images/Macroscopic Solutions)

A man carries his wife over an obstacle while competing in the Wife Carrying Championship to mark City Day in Krasnoyarsk, Siberia, Russia, June 25, 2016. (Photo by Ilya Naymushin/Reuters)

The 20-year-old American fashion model Kaia Jordan Gerber – who is the daughter of supermodel Cindy Crawford, 55, and businessman Rande Gerber, 59 – poses braless as she stuns in an edgy shoot in January 2022. (Photo by Ports 1961’s Spring/Summer Campaign)

Colombia's Harold Tejada climb Plateau des Glieres during the stage 18 of the Tour de France cycling race over 175 kilometers (108.7 miles) from Meribel to La Roche-sur-Foron, France, Thursday, September 17, 2020. (Photo by Thibault Camus/AP Photo)

Women members of the national police take part in a parade during a graduation ceremony in Bogota, Colombia on November 7, 2019. (Photo by Juan Barreto/AFP Photo)

German fan Didi Senft known as El Diablo cheers as the pack rides past during the 234.5 km seventh stage of the 101st edition of the Tour de France cycling race on July 11, 2014 between Epernay and Nancy, northeastern France. (Photo by Lionel Bonaventure/AFP Photo)

“El rio mas bonito del Mundo”, the most beautiful river of the world, the “River of five colors”, the “Rainbow River”, or even the “Escaped from Paradise”, are the shimmering appellations that Colombians give to Cano Cristales, a small stream located in the heart of the Macarena National Park, 150 km (93 miles) south of Bogota. Photo: A waterfall is seen at the end of the rainy season, in August, when the water level finally decreases, in the Cano Cristales RIver in the Sierra de la Macarena in Colombia. It has become covered with a bright pink endemic aquatic plant, Macarenia Clavigera. (Photo by Olivier Grunewald)