A picture made available on 08 July 2015 showsa lightning strikes during a heavy storm over Poznan in the night of 07 July 2015. Severe storms passed last night over Poland causing lots of damages to buildings, trees, electricity and railway tractions. (Photo by Lukasz Ogrodowczyk/EPA)

A girl uses her mobile phone during the evening at the National Park in Khartoum, Sudan, April 24, 2015. (Photo by Mohamed Nureldin Abdallah/Reuters)

A reveler jumps over a bonfire during the night of San Juan in Alcobendas near Madrid, Spain, Wednesday, June 24, 2015. The San Juan night coincides with the Summer solstice and it's the welcome to Summer. This celebration takes place during the shortest night of the year in almost all cities and towns of Spain. (Photo by Andres Kudacki/AP Photo)

Russian Mi-28N from the Berkuty (Golden Eagles) helicopter display team fly in formation during the “Aviadarts” military aviation competition at the Dubrovichi range near Ryazan, Russia, August 2, 2015. The aircraft started dipping down due to back propeller failure and crashed, killing one of two pilots, according to a Reuters photographer and official representatives of the competition. The aviation contest is part of the International Army Games, which are held in Russia from the 1st till the 15th of August with participants from 17 countries, according to organizers. (Photo by Maxim Shemetov/Reuters)

Arnaq Egede walks to the potato field on her family's farm on July 31, 2013 in Qaqortoq, Greenland. The farm, the largest in Greenland, has seen an extended crop growing season due to climate change. (Photo by Joe Raedle/Getty Images)

An Israeli soldier of the Caracal battalion smiles during a 23-kilometer march marking the end of their training in Israel's Negev desert, near Kibbutz Sde Boker February 14, 2013. The “Caracal” battalion, two-thirds of whose members are women, was established in 2004 with the purpose of incorporating female soldiers in combat units. The main mission of Caracal is routine patrols on Israel's border with Egypt to intercept infiltrators and smuggling from the Sinai desert. (Photo by Darren Whiteside/Reuters)

In this June 17, 2014 photo, a North Korean man takes shelter in the rain next to long propaganda billboards in the town of Samjiyon in North Korea's Ryanggang province. The Associated Press was granted to embark on a weeklong road trip across North Korea to the country’s spiritual summit Mount Paektu. The trip was on North Korea's terms. An AP reporter and photographer couldn't interview ordinary people or wander off course, and government “minders” accompanied them the entire way. (Photo by David Guttenfelder/AP Photo)

A performer from Cirque du Soleil's show “Quidam” practices backstage before a show at the MEO Arena in Lisbon December 18, 2014. (Photo by Rafael Marchante/Reuters)