Hemispheric color differences on Saturn's moon Rhea are apparent in this false-color view from NASA's Cassini spacecraft in this March 2, 2010 file photo. (Photo by Reuters/NASA/JPL/SSI)

People observe the landslide-affected area after the landslide at Lumle village in Kaski district July 30, 2015. Landslides triggered by torrential rain in Nepal swept through villages on Thursday, killing at least 30 people close to the nation's most popular trekking circuit, home ministry officials said. (Photo by Navesh Chitrakar/Reuters)

Lightning streaks across the sky as lava flows from a volcano in Eyjafjallajokul April 17, 2010. (Photo by Lucas Jackson/Reuters)

Zulmira Jesus poses for a portrait at a street in Povoa de Agracoes, near Chaves, Portugal April 19, 2016. In the villages of Agracoes and Povoa de Agracoe, the steady drip-drip of emigration has brought down population numbers from more than 50 residents to fewer than a dozen each. These remaining villagers share the same glum acceptance that, after they have gone, their villages will die out too. It is the same desolate picture in scores of other backwater settlements in Portugal's interior, north to south. (Photo by Rafael Marchante/Reuters)

The sun rises beside St Mary's Lighthouse in Whitley Bay, Tyne and Wear, as the unseasonably cool weather continues on Thursday, April 28, 2016. (Photo by Owen Humphreys/PA Wire)

An Iranian man sells colorful ropes at the Tehrans old Bazaar, the place where the main economy trades take place, in Tehran, Iran, 25 January 2016. Reports state that Iranian officials expected the Iranian economy to grow on an average of eight percent over the coming five years following the lifting of sanctions against Iran. (Photo by Abedin Taherkenareh/EPA)

The battle by Jose Garcia, US. Category: bird behaviour. A great white heron (Ardea herodias occidentalis) fighting a green snake in the Florida Everglades. The fight lasted for nearly 20 minutes with the heron having to release its prey. (Photo by Jose Garcia/2017 Bird Photographer of the Year Awards)

A car rolls south along the Dalton Highway near Coldfoot, Alaska, USA, 03 September 2017. Stretching 414 miles (666 kilometers) north from central Alaska to Prudhoe Bay, the Dalton Highway is one of America's northernmost roads and arguably its most remote. (Photo by Jim Lo Scalzo/EPA)