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)

This undated photo provided by the Ford Motor Co. shows the 1948 Lincoln Continental Cabriolet V12. Thirteen years after the last Continental rolled off a Michigan assembly line, Ford Motor Co. is debuting the new Continental in concept form at the New York Auto Show on Monday, March 30, 2015.The production version goes on sale next year. (Photo by AP Photo/Ford Motor Co.)

A Saudi soldier fires a mortar towards Houthi movement position, at the Saudi border with Yemen April 21, 2015. (Photo by Reuters/Stringer)

Jimmy Bryan of Phoenix, Ariz., gets the checkered victory flag at the Indiana State Fairgrounds September 17, 1955 as he wins the “Hoosier Hundred” for the second consecutive year. Bryan averaged 83.98 miles an hour for the 100-lap, 100-mile AAA big car race. (Photo by AP Photo)

Photo taken on November 5, 2015 shows flood in Bento Rodrigues, a town in the southeastern Brazilian state of Minas Gerais, after a dam at a mining waste site burst early Thursday. An iron ore tailings dam in the southeast Brazilian state of Minas Gerais collapsed Thursday, killing at least 15 people, according to local media reports. (Photo by Agencia Estado/Xinhua Press/Corbis)

This is the moment a diver appears to shake hands with a giant 52ft whale. The divers were just metres away when one humpback whale – which weighs 36,000kg – extends its giant flipper in a peaceful manner. (Photo by Masa Ushioda/SeaPics/Solent News & Photo Agency)

A curious leopard cub toys with a camera at MalaMala Game Reserve in Mpumalanga Province, South Africa. (Photo by Barcroft Media)

Marshalls try to get their hands on a streaker as golfers Michael Campbell of New Zealand and Paul McGinley of Ireland play the World Match Play final at Wentworth golf club some 20 miles west of London, 18 September 2005. Campbell won the title at the 17th hole. (Photo by Odd Andersen/AFP Photo)