In this Tuesday, March 10, 2015 photo, rime ice covers rocks on the summit of Mount Washington in New Hampshire. Rime ice occurs when freezing fog hits stationary objects in frigid conditions. (Photo by Robert F. Bukaty/AP Photo)

Aerial photo taken on March 4, 2017 shows cole flower fields in Luoping County, southwest China's Yunnan Province. (Photo by Xinhua/Barcroft Images)

An infrared portrait from NASA's Spitzer Space Telescope which shows generations of stars is seen in this undated NASA handout image released February 14, 2013. In this wispy star-forming region, called W5, the oldest stars can be seen as blue dots in the centers of the two hollow cavities (other blue dots are background and foreground stars not associated with the region). Red shows heated dust that pervades the region's cavities, while green highlights dense clouds. (Photo by NASA/Reuters/JPL-Caltech/Harvard-Smithsonian/Handout)

A dog sits in the shade of a mangrove tree as a woman uses a fork to dig for shellfish on the reef-mud flats of a lagoon located at South Tarawa in the central Pacific island nation of Kiribati May 23, 2013. Kiribati consists of a chain of 33 atolls and islands that stand just metres above sea level, spread over a huge expanse of otherwise empty ocean. With surrounding sea levels rising, Kiribati President Anote Tong has predicted his country will likely become uninhabitable in 30-60 years because of inundation and contamination of its freshwater supplies. (Photo by David Gray/Reuters)

Three very colouful alpacas enjoy the hot weather at Toft Farm, Rugby, on July 19, 2013. (Photo by Caters News)

Characters dressed as Elmo and Cookie Monster who pose for tips take a photo by request from a tourist (2nd R, black pants) in Times Square in the Manhattan borough of New York City, January 29, 2016. (Photo by Rickey Rogers/Reuters)

In this Friday, March 3, 2017 photo, a ribbon on a staff member's outfit blows in the breeze as she arrives for the opening session of the Chinese People's Political Consultative Congress (CPPCC) at the Great Hall of the People in Beijing. The annual session of China's ceremonial legislature is designed to awe onlookers with its size and sweep, yet the experience is also made up of tiny moments, details that point to the personalities of the participants and the event's unique, sometimes quirky, traits that a casual observer might easily miss. (Photo by Mark Schiefelbein/AP Photo)

“DC3 Wreck”. A capture of a US military DC3 plane wreck at the southern black beach in Iceland. Photo location: Iceland. (Photo and caption by Naian Feng/National Geographic Photo Contest)