1st Place in Wildlife: A male orangutan peers from behind a tree while crossing a river in Borneo, Indonesia. (Photo by Jayaprakash Joghee Bojan/National Geographic Nature Photographer of the Year contest 2017)

A duck swims in a Osterbekkanal during a the rainy autumn afternoon, central Hamburg, Germany 20 November 2017. (Photo by Srdjan Suki/EPA/EFE)

A gibbon drinks from a soft drink bottle, given by a tourist, at a zoo in Kunming, Yunnan province, June 18, 2015. (Photo by Wong Campion/Reuters)

People are reflected on a soap bubble lying on a road during the evening in New Delhi, India, June 23, 2015. (Photo by Anindito Mukherjee/Reuters)

Sara Moni, dressed as the World of Warcraft's Sinestra, poses for photographers on day three of the Comic-Con International held at the San Diego Convention Center Saturday July 23, 2016 in San Diego. (Photo by Denis Poroy/Invision/AP Photo)

In this photograph taken on August 25, 2016, an Afghan shepherd watches over his sheep as they graze on the outskirts of Herat. (Photo by Aref Karimi/AFP Photo)

Cloud inversion taken at Sunrise in Mam Tor, Derbyshire, UK on August 30, 2016. (Photo by David Zdanowicz/REX Shutterstock)

A towel with a print of the Nigerian naira is displayed for sale at a street market in the central business district in Nigeria's commercial capital Lagos February 4, 2016. (Photo by Akintunde Akinleye/Reuters)