Riot security forces clash with demonstrators as a motorcycle is set on fire during a protest against Venezuelan President Nicolas Maduro's government in San Cristobal, Venezuela May 29, 2017. (Photo by Carlos Eduardo Ramirez/Reuters)

Entomologist Anna Platoni wears a hat made of tropical flowers made by florist Emma Reynolds with a Blue Morpho butterfly on her cheek to mark the opening of Butterflies in the Glasshouse at RHS Garden Wisley, south of London, on Janurary 15, 2016. (Photo by Luke MacGregor/PA Wire/RHS)

Supporters of Ugandan President Yoweri Museveni celebrate his election victory in Kampala, Uganda February 20, 2016. Ugandan President Yoweri Museveni extended his 30-year rule on Saturday, winning an election that international observers said lacked transparency and his main opponent, who was placed under house arrest, denounced as a sham. (Photo by Goran Tomasevic/Reuters)

Labourers pour molten iron into a container at a foundry in Xiangfan, Hubei province in this July 2, 2010 file photo. Iron ore is enjoying its biggest rally in years, outpacing copper and oil so far in 2016, but still weak forward prices show it may be tough to stretch the bullish outlook. Improving steel prices in top market China are helping fuel iron ore's climb as producers gear up for a seasonal uptick in demand. Yet there is no shortage of doubters who see gains in the bulk commodity as fleeting given a large glut and challenges for China's economy. (Photo by Reuters/Stringer)

Paramilitary policemen carry tyres as they take part in a training session in Zhangye, Gansu Province, China, March 1, 2016. (Photo by Reuters/Stringer)

A flight deck crew prepares to launch a F18 Super Hornet from the deck of the USS Eisenhower off the coast of Virginia, December 10, 2015 in the Atlantic Ocean. US Defense Secretary Ash Carter visited the carrier with India's Minister of Defense Manohar Parrikar to demonstrate US Navy aircraft carrier flight operations. (Photo by Mark Wilson/Getty Images)

Relatives of the crashed AirAsia plane passengers pray at Juanda Airport, in Surabaya, Indonesia, 31 December 2014. Indonesian rescuers retrieved three more bodies from the sea on 31 December but the search to recover more victims from the AirAsia plane crash was hampered by bad weather, the recue chief said. AirAsia Indonesia flight QZ8501 crashed into the Java Sea on 28 December, about halfway through a two-hour flight between Surabaya, Indonesia's second largest city, and Singapore. (Photo by Made Nagi/EPA)

An artist from the state of Telangana reacts to the camera as they wait for their turn to perform during a media preview displaying a glimpse of culture of different parts of India, in New Delhi, India, Thursday, January 22, 2015. The tableaux will be part of the Indian Republic Day parade on Jan. 26. (Photo by Altaf Qadri/AP Photo)