A boy poses with a butterfly on his face during a photocall to promote the “Sensational Butterflies” exhibition at the Natural History Museum in central London, on March 25, 2013. With around 400 live tropical butterflies and moths living in the temporary facility, visitors will get the chance to see them flying freely as well as looking for emerging butterflies at the hatchery window. Running from March 29 to September 15, 2013, the exhibition is housed in a structure in the museum grounds. (Photo by Leon Neal/AFP Photo)

A man takes a photo of a radio antenna that's part of the Atacama Large Milimeter Array Observatory on March 12, 2013 at Llano de Chajnantor, about 43 miles (70 kilometers) from San Pedro de Atacama, Chile. The $1.5 billion ALMA facility, which had its official inauguration on March 13, is considered the world's most expensive ground-based observatory. (Photo by Felipe Trueba/EPA)

The book “Elektroschutz in 132 Bildern” (Electrical Protection in 132 Pictures) was published in Vienna in the early 1900s by a Viennese physician named Stefan Jellinek (1878-1968, a founder of the Electro-Pathological Museum). The pictures are nice and direct and unambiguous; they teach, graphically, that the surest way to kill yourself with electricity is to form a complete path from source (usually the bright red arrow) to ground (the screened back, pink arrow). Arrowheads provide the path for current flow. (Photo by The Vienna Technical Museum)

Li Tingting, second from right, laughs as she is lifted off the ground by her wife Teresa Xu, right, outside of a beauty salon where the two were preparing for their wedding as clerks from an adjacent shop look on in Beijing, Thursday, July 2, 2015. Li, a 25-year-old prominent women's rights activist who was released from detention in April, held the wedding ceremony with her partner Teresa on Thursday and announced their marriage in an effort to push for LGBT (lesbian, gay, bisexual, and transgender) rights in China. (Photo by Mark Schiefelbein/AP Photo)

Mrs. Marie Graskamp of Milwaukee shows the different positions one might assume when entering the bomb shelter in Milwaukee September 3, 1958. This circular entrance is about three feet in diameter. This is the entrance (according to the builders) that would connect to the cellar of a home assuming the shelter was in the ground for added protection. If a bombing should occur, all members of family would proceed to the cellar and then through the circular port into the shelter. (Photo by AP Photo)

Japanese Ground Self-Defense Force's 1st Airborne Brigade soldiers board a CH-47 helicopter for parachute drop training during their military drill at Higashifuji training field in Susono, west of Tokyo, July 8, 2013. Japan faces increasingly serious threats to its security from an assertive China and an unpredictable North Korea, a defence ministry report said on Tuesday, as ruling politicians call for the military to beef up its ability to respond to such threats. (Photo by Issei Kato/Reuters)

A cat tries to find dry ground around an apartment complex in Houston after Hurricane Harvey hit on Aug. 30. Harvey made landfall in South Texas on August 25, leading to days of downpours that dumped more than 50 inches of rain. Harvey damaged or destroyed about 200,000 homes as the storm system flooded much of Houston and smaller coastal communities. (Photo by Scott Olson/Getty Images)

Dont get catty. These roar-some images show the moment two female tigers came to blows in a bitter dispute over territory. Rarely ever seen in the wild let alone on camera, the dramatic images show a white Siberian tiger and orange-coloured tiger slashing ferociously at each others face and eyes. The intense altercation erupted into violence when the smallest of the pair, the orange striped tiger known as Shadow, attempted to expand its hunting ground. But white tiger, TiBo, wasnt willing to give up the ground without a fight and was forced to use its size and weight to put Shadow firmly back in her place. (Photo by Alex Kirichko/Caters News/SIPA Press)