A dejected German Grenadier carrying a machine gun on his shoulder in front of a building on fire during the German retreat in Russia. (Photo by Keystone/Getty Images). 1944

Yaks head towards the Everest base camp in Solukhumbu District April 28, 2014. (Photo by Navesh Chitrakar/Reuters)

Russian servicewomen march at Red Square during the Victory Day military parade in Moscow on May 9, 2017. Russia marks the 72nd anniversary of the Soviet Union's victory over Nazi Germany in World War Two. (Photo by Kirill Kudryavtsev/AFP Photo)

Brazilian Marcelo Medeiros of Yamaha team in an accident during the fifith stage of the Rally Dakar 2016 between Jujuy, Argentina, and Uyuni, Bolivia, 07 January 2016. (Photo by Felipe Trueba/EPA)

Behaviour: Mammals category. Giant Gathering by Tony Wu, USA. Dozens of sperm whales mingled noisily off Sri Lanka’s northeast coast, stacked as far down as Tony could see. This was a congregation of dozens of social units, like a gathering of the clans. Aggregations like this could be a critical part of the whales’ rich social lives but are rarely reported. Some two thirds of the population was wiped out before commercial whaling was banned in 1986. This kind of major gathering could be “a sign that populations are recovering”, says Tony. (Photo by Tony Wu/Wildlife Photographer of the Year 2017)

A hippopotamus performs during a show at the circus in Krasnoyarsk, Siberia, Russia, July 7, 2016. (Photo by Ilya Naymushin/Reuters)

Prepare yourself for some rib-tickling laughter because the Comedy Wildlife Awards has announced its finalists. Founded by Tanzania-based photographers Paul Joynson-Hicks MBE and Tom Sullam, the aim of the awards is to put a spotlight on wildlife conservation efforts while simultaneously injecting some humour into the world of wildlife photography. Here: Mountains Gorilla is making grimaces, as he came out of the bush after the rain, in Virunga National Park, Rwanda. (Photo by Josef Friedhuber/Comedy Wildlife Photography Awards/Barcroft Media)