A peformance artist attends an election rally for Cameroon presidential candidate for the opposition Univers party, Cabral Libii in Yaounde, Cameroon 06 October 2018. Africa's oldest president Paul Biya who has been in power since 1982 is up against eight candidates when voters go to the polls 07 October 2018. 6.9 million registered voters will head to the polls but marginalised anglophone separatists in the North West and South West of the country threaten to disrupt the elections. (Photo by Nic Bothma/EPA/EFE)

Mount Whaleback iron ore mine 23°21’32.3”S, 119°40’40.1”E. The Mount Whaleback Iron Ore Mine in the Pilbara region of Western Australia. Roughly 98% of the world’s mined iron ore is used to make steel and is thus a significant component in the construction of buildings, automobiles, and appliances such as refrigerators. (Photo by Daily Overview/DigitalGlobe, a Maxar Company)

Frost covers part of the face of University of Minnesota student Daniel Dylla during a morning jog along Mississippi River Parkway Tuesday, January 29, 2019, in Minneapolis. Extreme cold and record-breaking temperatures are crawling into parts of the Midwest after a powerful snowstorm pounded the region, and forecasters warn that the frigid weather could be life-threatening. (Photo by David Joles/Star Tribune via AP Photo)

Aerial view of tourists in life vests and rubber rafts in the Grand Canyon of western Henan, Sanmenxia, China on August 5, 2017. (Photo by Imaginechina/Rex Features/Shutterstock)

Two women wearing bejewelled bras kiss during the annual Sydney Gay and Lesbian Mardi Gras festival in Sydney, Australia March 4, 2017. (Photo by Jason Reed/Reuters)

In this May 2016 photo released by The Ocean Agency/XL Catlin Seaview Survey, a boat sails near a coral reef that has been bleached white by heat stress in the Maldives. oral reefs, unique underwater ecosystems that sustain a quarter of the world's marine species and half a billion people, are dying on an unprecedented scale. Scientists are racing to prevent a complete wipeout within decades. (Photo by The Ocean Agency/XL Catlin Seaview Survey via AP Photo)

From the “Paradise Revisited” story in the November 2013 issue of National Geographic magazine, this image is a beautiful vision of father and son fishermen as they move through the multicolored coral gardens of Kembe Bay, Papua New Guinea, in a traditional outrigger canoe. (Photo by David Doubilet/National Geographic Creative)

A stork-billed kingfisher (Pelargopsis capensis) is seen perched on a tree during monsoon rain on July 25, 2016 in Bintan, Indonesia. The stork-billed kingfisher is a tree species which is widely but sparsely distributed in the tropical Indian subcontinent and Southeast Asia, from India to Indonesia. This kingfisher is resident throughout its range. It is very large, measuring 35 to 38 cm (14 to 15 in) in length. The adult has a green back, blue wings and tail, and grey head. (Photo by Sijori Images/Barcroft Images)