Young man making the O.K. sign. (Photo by George Marks/Retrofile/Getty Images). Circa 1950s

Senator Barack Obama (D-IL) (R) stands in front of Senator Hillary Clinton (D-NY) as they arrive for U.S. President George W. Bush's annual State of the Union speech to a joint session of Congress at the U.S. Capitol in Washington in this January 23, 2007 file photo. Hillary Clinton announced her second run for the presidency on April 12, 2015 starting her campaign as the Democrats' best hope of fending off a crowded field of lesser-known Republican rivals and retaining the White House. (Photo by Larry Downing/Reuters)

Sydney artist Phillip George poses with two surfboards of his own design at Marks Park, Tamarama on December 16, 2008 in Sydney, Australia. (Photo by Don Arnold/Getty Images)

A soldier looks at a line during a ceremony to mark Martyrs' Day at the Tiananmen Square in Beijing, China, 30 September 2022. Martyr's Day is celebrated on the eve of National Day of the People's Republic of China to commemorate the people who sacrificed their lives in pursuit of national independence. (Photo by Mark R. Cristino/EPA/EFE)

Rita Ora leaving her hotel to go to BBC Children in need on November 07, 2018 in London, England. (Photo by Mark R. Milan/GC Images)

Astana Qazaqstan Team's British rider Mark Cavendish cycles past spectators in inflatable costumes during the 7th stage of the 111th edition of the Tour de France cycling race, 25,3 km individual time trial between Nuits-Saint-Georges and Gevrey-Chambertin, on July 5, 2024. (Photo by Anne-Christine Poujoulat/AFP Photo)

(2nd from R) Miss Georgia Betty Cantrell reacts to advancing, en route to victory, at the Miss America Pageant at Boardwalk Hall, in Atlantic City, New Jersey, September 13, 2015. (Photo by Mark Makela/Reuters)

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)