A salsa dancer performs in the “Salsodromo” parade, which marks the start of the Fair of Cali, Colombia, December 25, 2015. Picture taken December 25, 2015. (Photo by Jaime Saldarriaga/Reuters)

Boys pan for gold on a riverside at Iga Barriere, 25 km (15 miles) from Bunia, in the resource-rich Ituri region of eastern Congo February 16, 2009. Ituri is one of many areas of the country to have experienced bitter ethnic conflict between rival tribes in recent years. Massacres have left tens of thousands dead. It is this fighting that led U.S. authorities to take the unprecedented step of naming Congo in section 1502 of the Dodd-Frank financial regulation act, which says U.S.-listed companies that source gold, tungsten, tantalum and tin from Congo or its neighbours must assure the U.S. stock exchange regulator that their business is not helping fund conflict. (Photo by Finbarr O'Reilly/Reuters)

Two rainbows emerge from a black storm above the mountains, on August 19, 2014, in Kingman, Arizona. Double tornadoes, lightning storms and rotating supercells – this is what it's like to chase storms for a year. These dramatic images show apocalyptic weather throughout 2014 from a lightning storm to a pair of rainbows. Roger Hill, 57, has been chasing storms in the United States for thirty years and runs a tour operation with his wife Caryn. His favourite photograph of the year was also one of the most difficult to get – as two violent tornadoes tore through Pilger, Nebraska on June 16. The spiraling winds killed a five-year-old girl and injured at least 19 others, and as Roger tried to get the perfect shot debris began to rain down on his car. (Photo by Roger Hill/Barcroft Media)

A U.S. Air Force B-1B Lancer bomber sits on the runway at Anderson Air Force Base, Guam July 18, 2017. (Photo by Airman 1st Class Christopher Quail/Reuters/U.S. Air Force)

People visit the artwork titled Seven Magic Mountains by artist Ugo Rondinone, Wednesday, May 11, 2016, near Jean, Nev. The artwork was recently completed in the desert south of Las Vegas. (Photo by John Locher/AP Photo)

European Space Agency astronaut Tim Peake will return home after a six-month long mission on the International Space Station,on June 18, 2016. Peake was the first British ESA astronaut to visit the ISS and captured hundreds of photographs of the Earth during his mission. Here: “Lots of sun-glint right now during our whole orbit – we haven't seen a sunset for over 3 days”, he wrote. (Photo by Tim Peake/ESA/NASA)

Fans of Germany react as they watch the Euro 2016 match between France and Germany in France at a public screening of the match in Berlin, Germany, July 7, 2016. France won 2-0. (Photo by Hannibal Hanschke/Reuters)

Tiny pieces of space rocks, called meteorites, are seen burning in the atmosphere over the night sky near Salgótarján, some 109km northeast of Budapest, Hungary, 21 April 2018 (issued 22 April 2018). (Photo by Peter Komka/EPA/EFE)