A solar-powered plane takes off from Jiangbei International Airport in southwest China's Chongqing Municipality, Tuesday, April 21, 2015. The Solar Impulse 2 departed Chongqing on Tuesday for a 1190-kilometer (642-mile) flight to the city of Nanjing in eastern China, the sixth leg of its around-the-world flight. (Photo by Chinatopix via AP Photo)

A new species of monkey found in the Democratic Republic of the Congo and identified as Lesula (Cercopithecus lomamiensis) is seen in this undated photograph from an article published September 12, 2012 in the science journal PLOS One. The monkey was first seen in 2007 by researchers John and Terese Hart of the Peabody Museum of Natural History at Yale Research Project. The finding of C. lomamiensis represents only the second new species of African monkey to be discovered in the past 28 years, according to the research article. (Photo by Hart J. A., Detwiler K. M., Gilbert C. C./Reuters)

Claire Robertson from Scottish Ballet, poses dressed as the Good Snow Flake inside a life size snow globe on Buchanan Street during a promotion for Scottish Ballet’s festive production of The Nutcracker on November 20, 2012 in Glasgow, Scotland. The Nutcracker opens at the Theatre Royal on December the 8th, the production delves deep into the darker reaches of Hoffmann’s original tale in a fresh and vivid retelling of the famous Christmas story. (Photo by Jeff J. Mitchell)

Members of Brazil's Movimento dos Sem-Teto (Roofless Movement) stand in the hallway of one of the 11 empty buildings that the movement took over recently, in the centre of Sao Paulo, November 6, 2012. According to City Hall, there are some 400,000 people in need of stable housing, including the 4,000 families of the Roofless Movement who are squatting in abandoned or vacant buildings that range from apartment blocks to hotels, in Sao Paulo, the largest city in South America. (Photo by Nacho Doce/Reuters)

This July 2014 image provided by the Bureau of Land Management shows the interior of the Natural Trap Cave in north-central Wyoming. The cave holds the remains of tens of thousands of animals, including many now-extinct species, from the late Pleistocene period tens of thousands of years ago. Scientists have resumed digging for the first time in more than 30 years. (Photo by AP Photo/Bureau of Land Management)

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)

Xiren Wang, Lili Wat, and Sitong Chen join the pageant’s opening routine, dancing to “The Boys”, a song by K-Pop group «Girls’ Generation». While the women come from a range of professional backgrounds – including economics, nursing, and acting – every contestant is looking for her big break into the entertainment industry. Most contestants said they would prefer to have a career in the U.S. but would go wherever the opportunity lies. (Photo and caption by John Brecher/Sahra Vang Nguyen/NBC News)

Alaa, an ambulance driver, feeds cats in Masaken Hanano in Aleppo, September 24, 2014. Alaa buys about $4 of meat everyday to feed about 150 abandoned cats in Masaken Hanano, a neigbourhood in Aleppo that has been abandoned because of shelling from forces loyal to Syria's president Bashar Al-Assad on it. Alaa said that he has been feeding and taking care of the cats for over 2 months. (Photo by Hosam Katan/Reuters)