People cool off in a fountain outside the Southbank Centre on June 30, 2015 in London, England. The UK is currently experiencing a heatwave, with temperatures of 35 degree celsius forecast tomorrow in some parts of the country. The extreme heat has already seen train cancellations and a health warning has been issued. (Photo by Rob Stothard/Getty Images)

People on motor bikes celebrate American President Barack Obama's visit to Kenya by holding up a photo, center top, of the president and First Lady Michelle Obama in Kisumu, Kenya, Saturday, July 25, 2015. President Barack Obama heralded Africa as a continent “on the move” Saturday as he opened a U.S.-sponsored business summit in Kenya, the East African nation where he has deep family ties. (Photo by AP Photo)

Indian girls in traditional attire pose for photographs as they practice the Garba, the traditional dance of Gujarat state, ahead of Navratri festival in Ahmadabad, India, Saturday, October 3, 2015. Navratri or nine night festival will begin on October 13. (Photo by Ajit Solanki/AP Photo)

A protester with his face smeared with soot from burning barricades stands in the Musaga neighbourhood of Bujumbura on May 6, 2015. Government and opposition rivals are meeting in Burundi in a bid to end deadly demonstrations against a third term bid by the president, as regional foreign ministers arrived to add pressure. (Photo by Phil Moore/AFP Photo)

A toddler sits on the winner of the giant pumpkin category during the RHS (Royal Horticultural Society) London Harvest Festival Show at RHS Lindley Halls on October 6, 2015 in London, England. The traditional harvest themed show runs October 6-7 and showcases a wide range of late summer grown fruit and vegetables. (Photo by Ben Pruchnie/Getty Images)

A Palestinian young woman from the Birzeit University looks on during clashes with Israeli security forces in Beit El, on the outskirts of the West Bank city of Ramallah, on October 7, 2015. New violence rocked Israel and the Israeli-occupied West Bank, including a stabbing in annexed east Jerusalem, even as Israel and Palestinian president Mahmud Abbas took steps to ease tensions. (Photo by Abbas Momani/AFP Photo)

Riot police stand guard behind a fire as refinery workers hold a blockade of the oil depot of Douchy-Les-Mines to protest against the government's proposed labour reforms, on May 25, 2016. Refinery workers stepped up strikes that threaten to paralyse France weeks ahead of the Euro 2016 tournament as the government moved to break their blockades, escalating a three-month tug-of-war over labour reforms. (Photo by François L.O./AFP Photo)

A couple embrace during the start of the San Fermin festival in Pamplona, Spain July 6, 2016. Revelers from around the world kick off the festival with a messy party in the Pamplona town square, one day before the first of eight days of the running of the bulls. (Photo by Vincent West/Reuters)