A journalist takes photographs at the site of Thursday's Malaysia Airlines Boeing 777 plane crash near the settlement of Grabovo, in the Donetsk region July 18, 2014. World leaders demanded an international investigation into the shooting down of Malaysia Airlines Flight MH17 with 298 people on board over eastern Ukraine, as Kiev and Moscow blamed each other for a tragedy that stoked tensions between Russia and the West. (Photo by Maxim Zmeyev/Reuters)

Israeli soldiers detain a protester during a demonstration by Palestinians protesting against the Israeli-built West Bank separation barrier and calling for the right of return for Palestinian refugees, in the northern West Bank city of Tulkarem, on May 31, 2014. (AP Photo/Nasser Ishtayeh)

The Mercedes-Benz F015 Luxury in Motion autonomous concept car is shown on stage during the 2015 International Consumer Electronics Show (CES) in Las Vegas, Nevada January 5, 2015. (Photo by Steve Marcus/Reuters)

People take pictures of huge waves crash on the Viavelez seafront in the northern Spanish region of Asturias January 2, 2016. (Photo by Eloy Alonso/Reuters)

Two biplanes of the Team Breitling cross during a training flight prior the AIR14 air show in Payerne, Switzerland, August 29, 2014. (Photo by Peter Schneider/EPA)

An aerial view shows a sinkhole 3.5 km (2 miles) to the east of Solikamsk-2 mine in Perm region, November 20, 2014. Shares in Russia's Uralkali, the world's top potash producer, fell sharply for a second day on Wednesday after a mine accident that could reduce global supplies and push up prices of the crop nutrient worldwide. Uralkali shares have fallen 28 percent since Tuesday when it suspended work at its Solikamsk-2 mine, which accounts for a fifth of the company's output and 3.5 percent of global capacity, following an inflow of water. A sinkhole, stretching 30 by 40 metres (yards), found at an abandoned mine 3.5 km (2 miles) to the east, increased concern about the future of the mine because an inflow of water and the resulting sinkhole in 2006 forced another Uralkali operation to shut permanently. (Photo by Reuters/Press service of Uralkali company)

Believers burn dried oak branches, which symbolizes the Yule log, on Orthodox Christmas Eve in front of the St. Sava temple in Belgrade, Serbia, January 6, 2016. Serbian Orthodox believers celebrate Christmas on January 7, according to the Julian calendar. (Photo by Marko Djurica/Reuters)

A tribal fighter loyal to Yemen's government stands in Al Khurais village of Nihm district east of the capital Sanaa January 11, 2016. (Photo by Ali Owidha/Reuters)