Filipino mermaid swimming teacher Genevieve Reyes (C) has her tail adjusted by students during a lesson by the Philippines Mermaid Swimming Academy in a private swimming pool in Makati, Manila, Philippines, 15 June 2013. The Philippine Mermaid Swimming Academy (PMSA) was created in 2012 in Boracay by Normeth Preglo of The Philippines and US swimming instructor Djuna Rocha. The swimming lessons were brought to Manila in April 2013. The price for a two-hour class is 37 US dollars. (Photo by Dennis M. Sabangan/EPA)

Hitler, Hirohito and Mussolini, in effigy, are about to take a mile-high plunge over Stone Mountain, near Atlanta, Georgia, June 21, 1942, as part of the scrap rubber drive. Private Elias Nour, who arranged the stunt as a farewell party on the eve of his entrance into the army, is on the running board. He guided as the “Axis” plunged to destruction. Spectators had to give a scrap of rubber as the price of admission to the spectacle. (Photo by AP Photo)

A farmer and his cow “Cilly” wait for results of the “Milchgipfel” (lit. Milk summit) which takes place at the German Ministry of Food and Agriculture in Berlin, Germany on May 30, 2016. Minister of Food and Agriculture Christian Schmidt met with representatives of agriculture and dairy farming to evaluate measures to help dairy farmers in light of plummeting milk prices. (Photo by Maurizio Gambarni/EPA)

Frander Arroyo, select wings of butterflies at Blue Morpho Butterfly House in Alajuela, Costa Rica, March 10, 2016. According to Arroyo, owner of Blue Morpho Butterfly House, he collects dead butterflies from his garden to mount as handicraft like earrings, necklaces, paintings and rings for export with prices ranging from $12 to $16 a piece. (Photo by Juan Carlos Ulate/Reuters)

A Sotheby's employee holds a rare 52.82-carat white diamond ring at Sotheby's auction house on April 12, 2010 in London, England. Price: 7 million USD. (Photo by Dan Kitwood/Getty Images)

People line up to pay inside a Makro supermarket in Caracas, January 9, 2015. Venezuela's socialist government decreed an “economic emergency” on Friday that will expand its powers and published the first data in a year that shows the depth of a recession fueled by low oil prices and a sputtering state-led model. (Photo by Jorge Silva/Reuters)

Coloured X-ray of a barn owl. A physicist has used X-ray to create an extraordinary collection of artwork. Arie van't Riets pictures reveal birds, fish, monkeys and flowers in an incredible new light. The 66-year-old, from Bathmen in the Netherlands, began X-raying flowers as a means to teach radiographers and physicians how the machine worked. But after adding a bit of colour to the pictures, the retired medical physicist realised the potential for an exciting new collection of art. (Photo by Arie van't Riet/Barcroft Media)

In this photo taken in October 1917, provided by Russian State Documentary Film and Photo Archive, a machine gunner looks through a window at his position near the Kremlin in Moscow, Russia. The 1917 Bolshevik Revolution was long before the digital revolution allowed anyone to instantly document events. But the clumsy cameras of the time still caught some images that capture the period's drama. (Photo by Russian State Documentary Film and Photo Archive via AP Photo)