A woman holds newly designed Indonesia Rupiah banknotes after exchanging her old bills at a Bank Indonesia mobile bank in Jakarta, Indonesia December 19, 2016. (Photo by Fatima El-Kareem/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)

A Nepalese vetinary and technical team release a rhino after it is relocated in Chitwan National Park some of 250 Kilometer South of Kathmandu on April 4, 2017. Conservationists on April 3 captured a rare one-horned rhinoceros in Nepal as part of an attempt to increase the number of the vulnerable animals, which are prized by wildlife poachers. Five rhinos – one male and four female – will be released into a national park in Nepal's far west over the coming week in the hope of establishing a new breeding group. (Photo by Prakash Mathema/AFP Photo)

An Iraqi military vehicle passes displaced Iraqi boys returning to their homes in West Mosul's Oreibi neighbourhood after government forces retook control of the area from the Islamic State (IS) group during the ongoing offensive against the jihadists on May 21, 2017. (Photo by Ahmad Al-Rubaye/AFP Photo)

This August 15, 2016 photo shows two portraits Carolina, one of her holding a weapon while in her uniform for the Revolutionary Armed Forces of Colombia (FARC) 49th front, and in civilian clothing at a guerrilla camp in the southern jungle of Putumayo, Colombia. Carolina, 18, said she has spent three years in the FARC and would like to study engineering after demobilizing as part of a peace deal with Colombia's government. (Photo by Fernando Vergara/AP Photo)

The northern lights, or aurora borealis, illuminate the sky over Flakstad beach on Lofoten Islands in the Arctic Circle on September 5, 2017. (Photo by Jonathan Nackstrand/AFP Photo)

Trees in a park are illuminated with a red light as a part of an art project in Timmendorfer Strand, northern Germany Wednesday, October 26, 2016. (Photo by Michael Probst/AP Photo)

Border between Sweden and Norway at Moldusen. An approximately 20-meter wide clearing in the forest separates the two Scandinavian nations, consequently cutting Finnskogen in two. Grue Finnskog 2016. (Photo by Terje Abusdal/The Washington Post)