Visitors review their cell phone photos of an installation called “Plexus A1” by artist Gabriel Dawe, one of nine large-scale art installations displayed at the “Wonders” exhibit at the Renwick Art Gallery in Washington, DC, Wednesday, January 13, 2016. Built in the 1860s, the Renwick was the first American building to be designed specifically as an art museum; it recently reopened after a two year renovation. (Photo by Jim Lo Scalzo/EPA)

A child walks to an installation made from fallen leaves by college students, in shape of a sofa, to call for people's attention to environment protection, in Hangzhou, Zhejiang province, China, December 6, 2016. (Photo by Reuters/China Daily)

Cheng Liping, whose husband Ju was onboard Malaysia Airlines Flight MH370 which disappeared on March 8, 2014, shows a picture of she and her husband together and an old card with a message given by her husband, at a park near her house where she and her husband used to visit during an interview with Reuters in Beijing July 24, 2014. Cheng said her life has been totally changed since the incident. Their two little sons, who don't know about this incident, keep asking her when their dad is coming back. Six months after Malaysia Airlines Flight MH370, with 239 mostly Chinese people on board, disappeared about an hour into a routine journey from Kuala Lumpur to Beijing March 8, loved ones of missing passengers derive what comfort they can from what's left behind after the world's greatest aviation mystery. More than two dozen countries have been involved in the air, sea and underwater search for the Boeing 777 but months of sorties failed to turn up any trace – even after narrowing the search area to the southern Indian Ocean – long after batteries on the black box voice and data recorders had gone flat. (Photo by Kim Kyung-Hoon/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)

A young woman wearing no trousers hits the ski slopes at a ski resort in Xuzhou, in east China's Jiangsu province on January 13, 2015 in a promotional effort to equal “No Pants Subway Ride”, which was marked on January 11 this year. The promotional “No Pants Subway Ride” stunt on January 11 was held as commuters in some 60 cities around the world braved public transportation in their undies, which has gone global since its first staging by US group Improv Everywhere in New York in 2002. (Photo by AFP Photo)

Mario Huettenhofer, chief of the German company 3D Fab, presents his own face as 3d print during the international fairs FabCon 3.D and Rapid.Tech in Erfurt, Germany, Thursday, May 15, 2014. 130 exhibitors from all over the world present the entire world of 3D printing. The trade fairs are accompanied by specialist programs featuring 80 scientists, practitioners and trend analysts from ten countries, who will explain the latest findings, trends and applications for additive processes in industry and for 3D printing in the private sector to newcomers, experts and consumers alike. (Photo by Jens Meyer/AP Photo)

A Hindu holy man on his way to the annual holy dip at Gangasagar, gestures towards a visitor as he rests at a transit camp in Kolkata, India, Wednesday, January 6, 2016. Thousands of Hindu pilgrims are expected to take the annual holy dip at Gangasagar, where the Ganges River reaches the Bay of Bengal, on the auspicious Makar Sankranti festival day that falls on Jan.14. (Photo by Bikas Das/AP Photo)

In this June 1, 2016 photo, Maria Arias stands near her kitchen as she puts on earrings while getting ready for school in Caracas, Venezuela. So many students have fainted from hunger at Maria's school that administrators told parents to keep their children home until they could find more food. (Photo by Ariana Cubillos/AP Photo)