A rainbow is seen near a cloud south of Corvallis, Ore., Monday, May 19, 2014. (Photo by Andy Cripe/AP Photo/The Corvallis Gazette-Times)

Festival goers splash through a muddy puddle at Worthy Farm in Somerset, on the third day of the Glastonbury music festival June 27, 2014. (Photo by Cathal McNaughton/Reuters)

Recording artist Ariana Grande performs onstage during the 2014 iHeartRadio Music Festival at the MGM Grand Garden Arena on September 19, 2014 in Las Vegas, Nevada. (Photo by Kevin Winter/Getty Images for iHeartMedia)

A farmer harvests rice on a field in Lalitpur, Nepal, on October 30, 2014. (Photo by Navesh Chitrakar/Reuters)

Two young boys kneel on stools on either side of a round table as one uses a match to this the other's cigarette, November 12, 1928. (Photo by FPG/Getty Images)

An employee walks past a rotary dredge working at an open-cast iron ore mine of the Stoilensky mining and concentration plant (GOK), owned by the Novolipetsk (NLMK) steel mill, in the city of Stary Oskol in Belgorod region, Russia, August 4, 2015. (Photo by Maxim Shemetov/Reuters)

A worker walks through a salt pan on the eve of May Day or Labour Day on the outskirts of the southern Indian city of Chennai April 30, 2014. India is the third largest salt producing country in the world after China and U.S. with global annual production about 230 million tonnes, according to government data. (Photo by Reuters/Babu)

Egmont National Park in New Zealand with Mt. Taranaki at its center is seen in a Landsat 8 satellite image taken July 3, 2014 and released by NASA November 14, 2014. The image is from the book “Sanctuary: Exploring the World's Protected Areas from Space”, published by the Institute for Global Environmental Strategies with support from NASA, which was released this week. (Photo by Reuters/NASA/USGS)