Emperor penguins gathered together to keep their chicks warm in these pictures. Marine scientist Frederique Oliver snapped the protective parents in Antarctica as they huddled against the huge winds.The adorable birds have to battle temperatures on -20 degrees Celsius as well as winds of up to 40 knots on the ice. (Photo by Frederique Oliver/Caters News)

A graffiti, portraying a woman, is seen in Medellin, Colombia on November 19, 2017. Mural graffitis from different artists, street art can be seen in almost every city on Earth, but street arts raw power and potential for change was felt by me most intensively in Medellins Comuna 13, previously one of Colombias most dangerous neighbourhoods, in fact Communa 13 was constant battleground between gangs, narcos, paramilitaries and the government, but today you would hardly recognise it. (Photo by Juancho Torres/Anadolu Agency/Getty Images)

Police officers detain a Femen activist during a demonstration of supporters of former Spanish dictator Francisco Franco, during annual gathering held on the week of the 45th anniversary of the dictator's death, in Madrid, Spain, November 22, 2020. (Photo by Javier Barbancho/Reuters)

Protesters clash with police at Speakers Corner as thousands attend Unite For Freedom Against COVID-19 passports and vaccines in London, UK on April 24, 2021. People called online to a flash mob-style mass gathering against vaccine passport, face masks and lockdown. The government aims to provide official proof of vaccination for millions of British holidaymakers this summer starting as early as 17 May. (Photo by World Entertainment News Network)

These frozen caves seem almost otherworldly as they daylight illuminates them. Matej Kriz’s shots reveal the beauty of the brilliant caves, but he’s also very aware of how deadly they can be. The photographer captured the amazing shots in the Vatnajokull National Park on the Breidamerkurjokull glacier tongue. Here: The ice caves, taken in the Vatnajokull National Park in Iceland, on November 11, 2017. (Photo by Matej Kriz/Caters News Agency)

Tip turkey, dumpster chook, rubbish raptor – the Australian white ibis goes by many unflattering names. But it is a true urban success story, scavenging to survive in cities across Australia as wetlands have been lost. Wildlife photographer Rick Stevens captured them in Sydney. Here: Of all the species affected by river regulation in Australia, the ibis is one of the few that has changed its behaviour and moved to coastal cities. (Photo by Rick Stevens/The Guardian)

The Tree Projects team spent 67 days documenting one eucalyptus regnans in the Styx valley of Tasmania. Using a combination of tree-climbing and elaborate arboreal rigging techniques, they produced an intimate portrait from an impossible perspective of one of the world’s largest individual flowering trees, which goes by several common names. These photos document the process that resulted in an extraordinary ultra high-definition photograph. Here: Haley nears the top of the tree. (Photo by Steven Pearce/The Tree Projects/The Guardian)