Inflatable dolls in the shape of ducks are seen in front of the National Congress during a protest against tax increases in Brasilia, Brazil, March 29, 2016. The campaign “I will not pay the Duck” is organized by the Federation of Industries of Sao Paulo (FIESP) and uses the duck symbol in reference to industries that pay high taxes. (Photo by Gregg Newton/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)

Winter swimmers dressed in ballet costumes pose for a photo before diving into the icy water, during a snowfall at a park in Shenyang, Liaoning province, China on February 15, 2019. (Photo by Reuters/China Stringer Network)

A moon bear rests in a pool inside an enclosure at the Vietnam bear rescue centre, in Tam Dao national park, Vinh Phuc, Vietnam, 09 July 2019. The center is operated by international organization Animals Asia. There are currently 184 bears living at the the Vietnam Bear Rescue Centre. It is estimated that there are less than a few hundred bears left in the wild in Vietnam. According to the latest data from the Ministry of Agriculture and Rural development, around 600 bears are still being kept on farms. In Vietnam, Animals Asia has rescued a total of 209 sun bears and moon bears. (Photo by Minh Hoang/EPA/EFE/Rex Features/Shutterstock)

A Dead Leaf butterfly (Kallima inachu formosana, also called Orange Oakleaf Butterfly) rests on a tree trunk at the Taipei Zoo in Taipei, Tawian, 03 August 2019. Dead Leaf butterfly can be found in Tropical Asia from India to Japan. When its wings close, it resembles a dead leaf, providing camouflage against predators including birds, ants, spiders and wasps. (Photo by David Chang/EPA/EFE)

A camel performs during a “dance competition” held during the Pushkar Camel Fair in Pushkar, in the western state of Rajasthan, on November 5, 2019. Thousands of livestock traders from the region come to the traditional camel fair where livestock, mainly camels, are traded. The annual camel and livestock fair is one of the world's largest camel fairs. (Photo by Himanshu Sharma/AFP Photo)

British fashion model Twiggy plays around on the bumper cars at the Bertram Mills Circus in London, England on January 10, 1967. (Photo by AP Photo)

Iraq's second largest city, Mosul, is locked under the rule of extremists from the Islamic State group trying to purge it of everything they see as contradicting their stark vision of Islam. A trove of photographs now housed at the Library of Congress offers a glimpse of a different Mosul – before wars, insurgency, sectarian strife and now radicals' rule. The scenes were taken in the autumn of 1932 by staff from the American Colony Photo Department during a visit to Iraq at the end of the British mandate. (Photo by AP Photo)