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)

A tale of two foxes. Surprising behaviour, witnessed in Wapusk national park, on Hudson Bay, Canada, in early winter. Red foxes don’t actively hunt Arctic foxes, but where the ranges of two predators overlap, there can be conflict. Though the light was poor, the snow-covered tundra provided the backdrop for the moment that the red fox paused with the smaller fox in its mouth in a grim pose. (Photo by Don Gutoski/2015 Wildlife Photographer of the Year)

Workers attempt to bring a tranquillised black rhino to the ground before dehorning in an effort to deter the poaching of one of the world's endangered species, at a farm outside Klerksdorp, in the north west province, South Africa, February 24, 2016. (Photo by Siphiwe Sibeko/Reuters)

Students pose for a pictures taken by their friends during spring break on the beach in the resort city of Cancun, Mexico, February 27, 2009. (Photo by Israel Leal/AP Photo)

Child models present creations at Dong Wenmei T100 Children's Collection during China Fashion Week in Beijing October 29, 2014. (Photo by Kim Kyung-Hoon/Reuters)

“I started photography in June 2009. At the time, I was searching for a way to express both the rigorous scientist and the creative artist in me. There are few hobbies that let these two approaches work together, so I really was enthusiastic about it: I am now spending all my free time studying various techniques, contemplating others' fantastic work, and of course, making pictures”. – Christophe Kiciak. Photo: “The Hero”. (Photo by Christophe Kiciak)

Flores Rodriguez, of Puerto Rico, performs with his dough during the freestyle event, part of the Pizza World Championships, in Parma, northern Italy, Wednesday, April 17, 2013. The 22th edition of the championships run from April 15 to April 17. (Photo by Marco Vasini/AP Photo)