Tens of thousands of HIV positive prostitutes in the slums of Lagos to ensure a rapid spread of the epidemic. “If you arrive by car, you can smell the HIV virus outside”, joked my driver as we are on track to Badia a criminal slums of Lagos. Badia is a corruption of “Bad Area”. Nigerians have a lack of everything, except black humor. The poor West African country Nigeria, with a population of 140 million people, after India and South Africa the highest number of people with HIV / AIDS. (Photo by Ton Koene/Exclusivepix Media)

Young Christian Lebanese women, who are members of Kataeb Phalangist party, show their skill in handling arms while they train in a village between Christian-controlled eastern port of Jounieh and the Christian village of Zahle in the west Lebanon on September 9, 1976. The Lebanese civil war erupted in April 1975. (Photo by Erich Stering/AFP Photo)

“The Net thrower”. The fisherman are conducting activities on Situgunung Lake. Photo location: Situgunung lake, Sukabumi, West Java, Indonesia. (Photo and caption by Dody Kusuma/National Geographic Photo Contest)

The Bahamas, the Commonwealth nation of hundreds of islands roughly the size of Connecticut and with population of just a bit over Anaheim, is known for its crystal waters and pristine beaches. This is possibly one of the world’s most beautiful havens of nature, yet people are coming here to see pigs. It is unclear when the pigs first appeared on Exuma Island or where they come from. There’s talk about a daring escape from a shipwreck, or sailors releasing the swine on purpose. In all probability, there were no pigs on this tropical paradise before European settlers came, so their mere presence is the work of human. The intriguing feat of nature, however, is that this population of pigs developed a fine aptitude for swimming. Here: “So you're on a boat in Bahamas and then this pig swims by begging for food”. (Photo and caption by Lisa Larsen/Public Domain)

The lightest material ever made has been produced by a team of scientists in China, a Chinese university announced.

“Daredevil Nik Wallenda became the first person to walk on a tightrope across the Niagara Falls, taking steady, measured steps June 15, 2012 for 1,800 feet across the mist-fogged brink of the roaring falls separating the U.S. and Canada”. (Photo by John Moore/David Duprey/AP Photo)

Fabrice Monteiro travelled to the most polluted places in Africa and created terrifying characters who roamed their midst dressed in eerie debris. They are spirits, he says, on a mission to make humans change their ways. Informed by Africa’s environmental problems, Fabrice Monteiro’s photographs aim to highlight urgent ecological issues all over the world. His series “The Prophecy” is on show at Photo Basel 2017 until 18 June. (Photo by Fabrice Monteiro/Photo Basel 2017/Mariane Ibrahim Gallery/The Guardian)

A German rifleman beside the corpse of a French soldier in a trench at Fort Vaux, France, 1916. (Photo by Hulton Archive/Getty Images)