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 doll in a children's gas mask is seen amongst beds at a kindergarten in the abandoned city of Pripyat near the Chernobyl nuclear power plant in Ukraine on March 28, 2016. Deadly radiation still spews from Chernobyl 30 years after the worst nuclear meltdown in history, as a newly built giant arch is pulled into place to cover the stricken reactor for the next century. (Photo by Gleb Garanich/Reuters)

Sgt. William Olas Bee, a U.S. Marine from the 24th Marine Expeditionary Unit, has a close call after Taliban fighters opened fire near Garmsir in Helmand Province of Afghanistan, May 18, 2008. (Photo by Goran Tomasevic/Reuters)

Triston surfs a wave as his father, Todd, watches in Morro Bay. “Hes the most coordinated 3-year-old I've ever seen”, says the 35-year-old captain/paramedic with the Morro Bay Fire Department. (Photo by Joe Johnston/The Tribune of San Luis Obispo)

Bat seller Sukarwati shows a skinned bat on July 30, 2009 in Yogyakarta, Indonesia. Sukarwati and her family have hunted bats in the Imogiri region for generations, capturing more than 800 bats per month. The Sukarwati family believe that the meat from the bat heals asthma and respiratory problems and it is a great honour for them knowing that the meat that they provide will help ease people's health ailments. (Photo by Ulet Ifansasti)

Chrisitan pilgrims carry wooden crosses along the Via Dolorosa during the Good Friday procession on April 22, 2011 in Jerusalem, Israel. Thousands of Christians around the world will today mark Good Fiday when they commemorate the crucifixion of Jesus Christ. In Jerusalem Christian pilgrims took part in processions along the route that Jesus is believed to have taken in his last days as he carried the cross. (Photo by Uriel Sinai/Getty Images)

Vladimir Putin shows a hold to a young judo wrestler at the Regional Judo Center at the Arena Sports Complex in the Siberian city of Kemerovo on January 24, 2012, during his visit to the region. Putin is known for his passion for judo, in which he has a black belt. (Photo by AFP Photo/STR)

The First U.S. Spacewalk – Gemini 4 Ed White made the United States' first spacewalk on June 3, 1965 during the Gemini 4 mission. The extra-vehicular activity (EVA) started at 19:45 UT (3:45 p.m. EDT) on the third orbit when White opened his hatch and used the hand-held manuevering oxygen-jet gun to push himself out of the capsule. (Photo by NASA)