People walk along the Dune du Pilat (Dune of Pilat), the tallest sand dune in Europe, in La Teste de Buch, near Bordeaux, France, June 15, 2016. The dune has a volume of about 60,000,000 m³, measuring around 500 m wide from east to west and 2.7 km in length from north to south. Its height is currently 110 meters above sea level. (Photo by Sergio Perez/Reuters)

Filipino firemen extinguish a burning vehicle during an earthquake preparedness drill in Makati city, south of Manila, Philippines, 22 June 2016. Thousands of people participated in the Metro Manila earthquake drill to prepare residents of nearly 12 million for a feared magnitude-7.2 quake that could kill thousands and displace millions, Emerson Carlos head of the Metropolitan Manila Development Authority (MMDA) said. Philippines sits on the Pacific Ring of Fire, an area prone to seismic shifts that spark earthquakes and volcanic activity. (Photo by Francis R. Malasig/EPA)

Both men and women dressed as singer Kate Bush from her 1978 video to her song “Wuthering Heights” dance in a brief rehearsal before seeking to create a new world's record for the most people dancing in costume to the song at once at Tempelhofer Feld park on July 16, 2016 in Berlin, Germany. While a precise account was unavailable just after the event, a calculated estimate put the number of dancers at between 400 and 500, well above the previous record set in 2013 in Brighton, UK of 300. (Photo by Sean Gallup/Getty Images)

Children surround a man, left, that fell down while walking on a street suspected of having contracted the Ebola virus in the city of Monrovia, Liberia, Tuesday, August 19, 2014. The World Health Organization says the outbreak has killed more than 1,200 people, while authorities struggle to contain its spread and treat the sick. (Photo by Abbas Dulleh/AP Photo)

People look at French artist Clement Briend's photographic light installation “Divine Trees”, which features images of divine figures highly revered in Asian cultures projected on trees towering over bystanders, during a media preview of the Singapore Night Festival in Singapore August 21, 2014. The Singapore Night Festival begins on Friday. (Photo by Edgar Su/Reuters)

Dillon Bracken (L) and Atalya Stachel dance during the Burning Man 2014 “Caravansary” arts and music festival in the Black Rock Desert of Nevada, August 30, 2014. Over 65,000 people from all over the world have gathered at the sold out festival to spend a week in the remote desert cut off from much of the outside world to experience art, music and the unique community that develops. (Photo by Jim Urquhart/Reuters)

A box of 36 coloured pencils as photographed in a studio with an illustrative price tag of $115 (US dollars), equivalent to the Bs. 725 (bolivars) that it costs on average to purchase in Caracas at the official exchange rate of 6.3 bolivars per dollar, in Caracas September 29, 2014. Venezuela's economic crisis has led to some shocking and surreal price distortions that hit people's buying power dramatically. (Photo by Carlos Garcia Rawlins/Reuters)

A demonstrator throw a firebomb during clashes with Turkish riot police officers in Istanbul, Turkey, Friday, May 1, 2015. The government assigned 30,000 police officers backed by helicopters as workers and demonstrators determined to defy a government ban, tried to march to iconic Taksim Square, where 35 people were killed during May Day celebration in 1977. (Photo by Emrah Gurel/AP Photo)