A girl carries a bag of recyclable items she collected from a landfill on the outskirts of Sanaa, Yemen November 16, 2016. (Photo by Mohamed al-Sayaghi/Reuters)

A Thai traffic security guard wears a Santa Claus costume as he directs the traffic on a street during Christmas celebrations outside a shopping mall in Bangkok, Thailand, 22 December 2015. The campaign of a shopping mall is held to celebrate the upcoming Christmas season and to attract shoppers. (Photo by Narong Sangnak/EPA)

Team McLaren Mercedes drivers Lewis Hamilton (L) and Jenson Button unveil the new MP-27 Formula 1 car at the McLaren technology centre on February 1, 2012 in Woking, England. (Photo by Mark Thompson/Getty Images)

1: Dubai's Burj Khalifa is the tallest building in the world, but perhaps not for long. Saudi Arabia has announced plans to build a 1 kilometer (3,280 foot) tower into the sky, to be named the Jeddah Tower, scheduled for completion in 2020. The Burj Khallifa currently stands at 2,716 ft. (Photo by Matthias Seifert/Reuters)

First graders of a cadet's lyceum attend a ceremony to mark the start of the new school year in Kiev, Ukraine, September 1, 2015. September 1 marks the start of a new academic year for students in Ukraine.(Photo by Valentyn Ogirenko/Reuters)

An Airbus A400M military aircraft lands at the ILA Berlin Air Show in Schoenefeld, south of Berlin, Germany, June 1, 2016. The Aerospace Exhibition at Schoenefeld Airport near Berlin takes place from June 1 till 4. (Photo by Fabrizio Bensch/Reuters)

Badminton School sixth form pupils (L-R) Lucy Warden, who got 3 A* and is off to study English at Durham, Sam Crumpton, who got 1 A* and 2 A's and is off to study to be a vet at Cambridge and Madeline Sunter, who got 2 A* and 1 B, and is off to study fashion at St. Martins, celebrate their A-level results on August 18, 2011 in Bristol, England. With another record year for A-level results, sixth-form students face a scramble for university places in the final year before tuition fees rise. According to the examination bodies the pass rate rose for the 29th successive year to hit 97.8 percent, while around one in 12 exams achieved the top A* grade. (Photo by Matt Cardy/Getty Images)

Revellers react after falling in the mud at Worthy Farm in Somerset during the Glastonbury Festival, Britain, June 26, 2016. (Photo by Stoyan Nenov/Reuters)