Bebe Rexha performs on stage at the 2016 MTV Europe Music Awards at the Ahoy Arena in Rotterdam, Netherlands, November 6, 2016. (Photo by Yves Herman/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)

Ricky Martin perfoms "La Mordidita" during the Latin Recording Academy Person of the Year gala honoring Brazilian singer Roberto Carlos in Las Vegas, Nevada November 18, 2015. (Photo by Mario Anzuoni/Reuters)

Host Jennifer Lopez performs during the 2015 American Music Awards in Los Angeles, California November 22, 2015. (Photo by Mario Anzuoni/Reuters)

The fourth annual BigPicture Natural World Photography Competition aims to celebrate the diversity of life on Earth, and encourages people to protect and conserve it. Here: “The Salmon Catchers”. Terrestrial Wildlife. To capture this view of a mother grizzly bear and her cub, photographer Peter Mather set up a camera trap on a log that he knew the bears tended to traverse while fishing for salmon, in the Yukon River watershed in Canada. (Photo by Peter Mather/BigPicture Natural World Photography Competition 2017)

A competition, now in its 43rd year, dedicated to showcasing the beautiful and bizarre as seen under a light microscope attracted over 2,000 entries from 88 countries. Here: Honorable Mention by Emre Can Alagöz, Istanbul, Turkey: The eyes of a jumping spider, magnified 6x. (Photo by Emre Can Alagöz/2017 Nikon Small World Photomicrography Competition)

The Invasion. A quiet street in Macau. Modernization around is quickly changing the city, as documented by Paul Tsui. (Photo by Paul Tsui/National Geographic Travel Photographer of the Year Contest)

Best portfolio winner. Roseate Spoonbill, Platalea ajaja, by Petr Bambousek, Czech Republic. (Photo by Petr Bambousek/2018 Bird Photographer of the Year)