The crowd watches as stunt pilots Melissa Pemberton, Jurgis Kairys and Skip Stewart of The Immortals fly past pyrotechnics as they perform at The Australian International Airshow on March 1, 2015 in Avalon, Australia. (Photo by Scott E. Barbour/Getty Images)

A swimmer reacts after finishing his competition in a pool carved into thick ice covering the Songhua River during the Harbin Ice Swimming Competition in the northern city of Harbin, Heilongjiang province January 5, 2015. The swimming competition was held on the official launch day of the Harbin International Ice and Snow Sculpture Festival. (Photo by Kim Kyung-Hoon/Reuters)

An engineer (L) talks to a driver of a dump truck loaded with gold-bearing soil at the Vostochny opencast of the Olimpiada gold operation, owned by Polyus Gold International company, in Krasnoyarsk region, Eastern Siberia, Russia, June 30, 2015. Polyus Gold International is the largest gold producer in Russia and one of the top 10 gold miners globally by ounces produced, according to the official web site of the company. Olimpiada is Polyus Gold's largest operation. (Photo by Ilya Naymushin/Reuters)

A prototype Rollkers transportation device is displayed during a press event at the Mandalay Bay Convention Center for the 2015 International CES on January 4, 2015 in Las Vegas, Nevada. The product is not a skate; it balances for you and when you place it on the bottom of your shoe, it gives you the ability for faster transportation based on walking. The balance CES, the world's largest annual consumer technology trade show, runs from January 6-9 and is expected to feature 3,600 exhibitors showing off their latest products and services to about 150,000 attendees. (Photo by Ethan Miller/Getty Images)

The Soyuz TMA-19M spacecraft is mounted on a launch pad at the Russian-leased Baikonur cosmodrome in Kazakhstan early on December 13, 2015. Russia's Soyuz TMA-19M spacecraft carrying the International Space Station (ISS) Expedition 46/47 crew of Britain's astronaut Tim Peake, Russian cosmonaut Yuri Malenchenko and US astronaut Tim Kopra is scheduled to blast off to the ISS on December 15, 2015. (Photo by Kirill Kudryavtsev/AFP Photo)

Farmers harvest cocoa fruits at a plantation in Gantarang Keke Village, South Sulawesi, Indonesia May 8, 2015. Sulawesi is at the heart of Asia's largest cocoa producing region, and is where some international confectioners are looking to boost output to feed growing demand for chocolate in the region. (Photo by Yusuf Ahmad/Reuters)

An exhausted and frustated migrant holds his head after he missed to get a place on a train heading to the Serbian border at the train station in Gevgelija, The Former Yugoslav Republic of Macedonia, August 13, 2015. From the beginning of the year to mid-June 2015, nearly 160,000 migrants landed in the southern European countries, mainly Greece and Italy, on their way to wealthier countries in Western and Northern Europe, according to estimates by the International Organization for Migration (IOM). (Photo by Georgi Licovski/EPA)

Policemen take pictures of the Soyuz TMA-17M spacecraft while it is transported from an assembling hangar to its launch pad at the Baikonur cosmodrome, Kazakhstan, July 20, 2015. The Soyuz is scheduled to blast off with Kjell Lindgren of the U.S., Kimiya Yui of Japan and Oleg Kononenko of Russia to the International Space Station on July 23, 2015. (Photo by Shamil Zhumatov/Reuters)