Farmer Zhang Xianping rides his pig "Big Precious" during an interview with the media, in Zhangjiakou, Hebei province, China, November 2, 2015. Zhang, a pig breeder, instead of killing it, decided to keep the two-year-old "Big Precious" as pet when its weight reached 600 kg, according to local media. (Photo by Reuters/China Daily)

Fashionistas pose for photographs in front of a homeless man outside Moynihan Station following a showing of the Rag & Bone Spring/Summer 2013 collection during New York Fashion Week in this September 7, 2012 file photo. (Photo by Lucas Jackson/Reuters)

A caterpillar driven ferry with a 24 horsepower engine takes holidaymakers from the mainland at Bigbury in Devon to Burgh Island, a quarter of a mile away. (Photo by Reg Speller/Fox Photos/Getty Images). 4th April 1935

Audrey Tautou poses at a photo call during The 66th Annual Cannes Film Festival at at Palais des Festivals on May 14, 2013 in Cannes, France. (Photo by Valery Hache/AFP Photo)

Blizzard in the High Peak, Derbyshire, by John Finney: “After a difficult journey in the snow, I made my way from Mam Tor down onto the Great Ridge. As the clouds got darker, I placed the tripod and camera at just the right angle to avoid snow getting onto the lens, and used a flash gun and a relatively slow shutter speed to highlight the fast motion of the blizzard”. Classic view, adult class – winner. (Photo by John Finney/Landscape Photographer of the Year)

A quake-resistant dome house decorated with Japan's popular “Kumamon” bear character is pictured at the Aso Farm Land resort in Aso, Japan on November 6, 2017. Cabins modelled after Japanese sweets and made from polystyrene foam withstood last year's deadly earthquakes in Kumamoto prefecture. (Photo by Kim Kyung-Hoon/Reuters)

The 26th annual National Geographic Traveler Photo Contest is now accepting submissions. Official categories include: “Travel Portraits”, “Outdoor Scenes”, “Sense of Place” and “Spontaneous Moments”. The contest is accepting entries until June 30. Photo: “Forest lights”. Aurora Borealis over the forest of the Pyhae Luosto National Park, Finland. (Photo and caption by Nicholas Roemmelt/National Geographic Traveler Photo Contest)

This composite image shows a sequence, from bottom left to top left, of the moon's transition during a total lunar eclipse on April 15, 2014 in Miami, Florida. People in most of north and south America should be able to witness this year's first total lunar eclipse, which will cause a “blood moon” and is the first of four in a rare Tetrad of eclipses over the next two years. (Photo by Joe Raedle/Getty Images)