Soldiers of China's People's Liberation Army (PLA) jump as part of their winter training in temperature of negative 26 degrees Celsius at China's border with Russia in Heihe, Heilongjiang province, December 14, 2015. (Photo by Reuters/Stringer)

Tourists watch the Christmas Day sunrise behind Diamond Head from Waikiki Beach in Honolulu, Friday, December 25, 2015. (Photo by J. David Ake/AP Photo)

A salsa dancer performs in the “Salsodromo” parade, which marks the start of the Fair of Cali, Colombia, December 25, 2015. Picture taken December 25, 2015. (Photo by Jaime Saldarriaga/Reuters)

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

“After an afternoon of hiking and exploring the caves of Rhossili Bay, West Glamorgan, we caught the sun breaking through the clouds”. (Photo by Megan Warren-Davis/The Guardian)

A visitor kneels down nex to an iCub robot made by the Italian Institute of Technology at the scientists congress IROS 2015 in Hamburg, Germany October 2, 2015. The robot congress is organized by TAMS group (Technical Aspects of Multimodal Systems) of Hamburg's university. (Photo by Fabian Bimmer/Reuters)

The CBRE Urban Photographer of the Year competition – now in its ninth year – encourages professional and amateur photographers to capture cities at work. Here: Dog Walker – 15:00. The competition allows photographers to enter up to 24 images, one representing each hour of the day. (Photo by Johanna Siegmann)