Contestants of a tattoo competition pose for photographs at the China TATTOO convention in Nanning, Guangxi Zhuang Autonomous Region, China, October 24, 2015. The annual convention was held in Nanning from October 23 to 25 this year. (Photo by Reuters/Stringer)

In this photo taken on Monday, January 5, 2015, a mallard duck attempts to walk on a frozen pond in Yukon, Okla. (Photo by Steve Gooch/AP Photo/The Oklahoman)

Paramilitary policemen take part in a training in Chaohu, Anhui province, China December 28, 2015. (Photo by Reuters/China Daily)

Dutch artist Maxim Gazendam works on his sand sculpture during the third edition of the European Championship Sand Sculpting 2014 in Zandvoort aan Zee, The Netherlands, 08 August 2014. Eight sculptors from different European countries will each create an impressive sculpture on the main theme “Music and Dance”. (Photo by Remko De Waal/EPA)

A competitor shows her tattoos at the MBK Tattoo Contest in a shopping mall in Bangkok October 23, 2014. (Photo by Athit Perawongmetha/Reuters)

The Mexico – United States barrier – also known in the United States as the border fence, rotted fence or border wall – is actually several separation barriers designed to prevent illegal movement across the Mexico – United States border.

“Slow”. A calm cow in the messy streets of Jodhpur. Photo location: India. (Photo and caption by Matthias Troeger/National Geographic Photo Contest)