A pilot steers his helicopter at night over Rio de Janeiro, Brazil, less than two weeks before the start of the Rio 2016 Olympic Games, July 23, 2016. Picture taken July 23, 2016. (Photo by Pawel Kopczynski/Reuters)

For her series “Dolce Vita in Hell”, Swiss photojournalist Stéphanie Buret headed to Eritrea and found a country struggling to haul itself out of oppression – but with its art deco buildings still looking stunning. (Photo by Stéphanie Buret/The Guardian)

These images of abandoned hospitals across Italy are not for the faint-hearted. Both of the hospitals featured in the photographs are Italian asylums – known as manicomios – that were used as mental hospitals. Shut down by law in 1978, the derelict buildings are visibly overgrown and make for very eerie portraits. Photographer Thomas Windisch, 32, of Graz, Austria, said the asylums, located in top-secret spots, can get very creepy when there aren't many people there with him. Here: a hallway within an abandoned hospital. (Photo by Thomas Windisch/Caters News)

Migrants wait to cross the Slovenia-Austria border in Sentilj, Slovenia, October 27, 2015. The first five border guards – all German – of 400 promised to Slovenia by fellow EU countries are expected to arrive on Wednesday to help channel a huge flow of migrants through the tiny Alpine state, its government said. Interior Ministry state secretary Bostjan Sefic also said 100-120 customs police would join Slovenian soldiers, regular police and private security firms in dealing with an influx that has strapped the country's limited resources. (Photo by Srdjan Zivulovic/Reuters)

Haitian policemen arrest a demonstrator with machetes at the end of a march, in Port-au-Prince, on November 26, 2015. Supporters of Fanmi Lavalas and Petit Dessalines political parties marched to protest against the results given by the Provisional Electoral Council (CEP), against the Haitian President Michel Martelly, and against the candidate of the ruling party Jovenel Moise. Provisional Electoral Council (CEP) confirmed this week that Haiti's presidential election will go to a runoff on December 27, between ruling party candidate Jovenel Moise and Jude Celestin, close to former president Rene Preval. (Photo by Hector Retamal/AFP Photo)

A homeless man rests on the side of a street at the old quarter of Yemen's capital Sanaa November 27, 2015. (Photo by Khaled Abdullah/Reuters)

A man smiles as he carries firewood he bought on a street amid ongoing fuel and cooking gas shortages in Yemen's capital Sanaa December 2, 2015. (Photo by Khaled Abdullah/Reuters)

Shimmering clearest blue and stretching as far as the eye can see, this is one of Iceland's famed crystal ice caves. The giant solid waves look frozen in time but they are slowly moving along as part of the Vatnajokull Glacier – which stretches across eight per cent of the island. The images were captured in February 2014 by British photographer Rob Lott, 49. Photo: A wide view of Rob Lott in the crystal ice cave in the Vatnajokull Glacier, Iceland. (Photo by Rob Lott/Barcroft Media)