Pope Francis greets the crowd from his popemobile in downtown Rio de Janeiro. Pope Francis touched down in Rio de Janeiro on Monday, starting his first foreign trip as pontiff and a weeklong series of events expected to attract more than a million people to a gathering of young faithful in Brazil, home to the world's largest Roman Catholic population. (Photo by Ueslei Marcelino/Reuters)

“The Amazon river has a newly discovered source. Completed last year and led by West Hansen and documented by award-winning freelance photographer Erich Schlegel, this is the first expedition to paddle from the furthest source of the earth's largest river to the ocean”. – zReportage. Photo: August 19, 2012 – Alpamarca, Peru – Amazon Express white water members Juan Antonio De Ugarte, of Peru, Rafael Ortiz, of Mexico, West Hansen, of the U.S., and Tino Specht, of the U.S., paddle down the Rio Gashan after leaving Lago Acucocha. Lago Acucocha is possibly the dry season source of the Amazon River. (Photo by Erich Schlegel/zReportage via ZUMA Press)

Keep your eyes peeled: A Chinese teenager slipped and stabbed himself in the face with a 7cm knife while peeling an apple. Ren Hanzhi's father recalled: “He was walking to the sofa while peeling the apple. Suddenly he slipped down and his face hit onto the sharp knife. I dared not pull out the knife as my son was screaming”. The nearest hospital referred the 13-year-old to a larger unit. Chief surgeon Peng Liwei, who operated to remove the knife, commented: “It's shocking. The knife, which is more than 20cm long, penetrated 7cm into his face. The surgery was successful and the patient could recover fully in around a month”. (Photo by Rex Features)

The Red Arrows make a flypast during the Trooping The Colour parade at Buckingham Palace, in London, Saturday, June 13, 2015. Hundreds of soldiers in ceremonial dress have marched in London in the annual Trooping the Color parade to mark the official birthday of Queen Elizabeth II. The Trooping the Color tradition originates from preparations for battle, when flags were carried or "trooped" down the rank for soldiers to see. (AP Photo/Tim Ireland)

Tourists and journalists stand next to a newly displayed statue of pharaoh Amenhotep III and his wife Tiye (Down) in Egypt's temple city of Luxor on March 23, 2014. Two colossal statues of pharaoh Amenhotep III were unveiled by archaeologists today in their original sites in the funerary temple of the king, on the west bank of the Nile in Luxor, adding to the existing two famous ancient Memnon colossi. (Photo by Khaled Desouki/AFP Photo)

“Strike Through The Mothership”. Every May for the last 3 years I have driven down to Tornado Alley to capture some amazing storms. This supercell held so much promise to drop a tornado but one small shift in the atmosphere and all that it produced was an extreme lightning show. Photo location: Broken Bow, Nebraska. (Photo and caption by Vanessa Neufeld/National Geographic Photo Contest)

A demonstrator argues with policewomen after she turned up her shirt and was taken out from a protest to demand the resignation of Brazilian President Dilma Rousseff, on March 13, 2016 in Paulista Avenue in Sao Paulo. Protesters, many draped in the Brazilian national flag, poured into the streets of Brasilia and Rio de Janeiro on Sunday at the start of mass demonstrations seeking to bring down President Dilma Rousseff. Authorities in Sao Paulo, Brazil's biggest city and an opposition stronghold, said they were bracing for a million protesters. (Photo by Miguel Schincariol/AFP Photo)

Half-naked girls against speed driving in Nizhny, Novgorod Region, Russia on September 5, 2016. Russian drivers are getting quite an eyeful in a bid to make them slow down thanks to topless women flashing speed limit signs at an accident blackspot. A trial of the road safety campaign demonstrated that it helped lower the speed of traffic near a pedestrian crossing in Severny village. (Photo by YouTube)