People ride on a truck as they return to their families ahead of the Eid al-Adha festival in Khartoum September 11, 2016. (Photo by Mohamed Nureldin Abdallah/Reuters)

Dancers from the “Legend Lin Dance Theatre” perform the artistic director and choreographer Li-chen Lin's classic works “Hymne aux Fleurs qui Passent, Anthem to the Fading Flowers” during a rehearsal at the National Theater Concert Hall in Taipei, Taiwan, Tuesday, August 18, 2015. “Hymne aux Fleurs Qui Passent” pays tribute to the cycle of the year and the complementary principles of Yin and Yang whose eternal struggle provides the driving force behind the changing of the seasons. (Photo by Chiang Ying-ying/AP Photo)

Elementary school children play outside their classrooms as mount Sinabung volcano spews thick volcanic ash in the background on February 10, 2017 in Karo, Indonesia. Mount Sinabung is one of the most active volcanoes in Indonesia and last erupted in May 2016, killing seven people. (Photo by Albert Damanik/Barcroft Images)

A young woman cools herself in a fountain in Budapest, Hungary July 6, 2015. Over the weekend, a heat wave has reached Hungary with temperatures topping 38 degrees Celsius (100.4 degrees Fahrenheit). (Photo by Laszlo Balogh/Reuters)

Kyrgyz men on horseback compete during their traditional game of “Oodarysh” during the celebrations of the 90th anniversary formation of the Chui region in the village of Kuntu some 20 kms from Bishkek on May 27, 2016. (Photo by Vyacheslav Oseledko/AFP Photo)

Star Wars fan Mike Deguzman practices with a toy lightsaber after purchasing some new toys that went on sale at midnight in advance of the film “Star Wars: The Force Awakens” in Times Square in the Manhattan borough of New York, September 4, 2015. (Photo by Carlo Allegri/Reuters)