Shoppers walk down stairs featuring a five-metre-high reproduction of Vincent van Gogh's signature painting “Sunflowers”, at the entrance to Ocean Terminal in Hong Kong July 15, 2013. A premium three-dimensional reproduction of works of Van Gogh, the RELIEVO collection, approved by the curators of the Van Gogh Museum in Amsterdam, is on display at a gallery inside Harbour City shopping mall attached to the terminal. (Photo by Bobby Yip/Reuters)

Swiss rescue workers wheel a wounded person on a stretcher after two regional trains crashed head on near Granges-Pres-Marnand near Payerne in western Switzerland July 29, 2013. The two trains collided in the Swiss canton of Vaud on Monday evening, injuring about 40 people, four seriously, Swiss news agency ATS reported. There was no immediate report of any deaths in the crash. (Photo by Denis Balibouse/Reuters)

Gers, traditional Mongolian tents, are seen on a hill in an area known as a ger district in Ulan Bator June 26, 2013. Approximately 60 percent of the population of Ulan Bator live in settlements known as ger districts and in many cases residents have limited access to basic services such as water and sanitation. According to a 2010 National Population Center census, every year between thirty and forty thousand people migrate from the countryside to the capital Ulan Bator. Ger districts in the city have been expanding rapidly in recent years. Mongolia is the world's least densely populated country, with 2.8 million people spread across an area around three times the size of France. (Photo by Carlos Barria/Reuters)

Autos sit on top of each other in a washed out section of Dog Track Road in the Millview community as Gulf Coast residents continue cleaning up from damage caused by torrential rains in Pensacola, Fla., Thursday, May 1, 2014. The National Weather Service, estimated 15-20 inches of rain has fallen in the Pensacola area in the past 2 days. (Photo by G. M. Andrews/AP Photo)

Tourists take a “selfie” as demonstrators burn a trash container during a May Day rally in Barcelona, Spain, on May 1, 2014. Tens of thousands of workers marked May Day in European cities with a mix of anger and gloom over austerity measures imposed by leaders trying to contain the eurozone's intractable debt crisis. (Photo by Manu Fernandez/Associated Press)

A young performer cries as she parades during the Bun Festival on Cheung Chau island in Hong Kong Tuesday, May 6, 2014. Bun Festival, the Taoist God of the Sea, is worshipped and evil spirits are believed to be scared away by loud gongs and drums during the procession. The celebration includes bun scrambling, parades, opera performances, and children dressed in colorful costumes. (Photo by Kin Cheung/AP Photo)

A “Maya” girl sits in an altar during the traditional celebration of “Las Mayas” on the streets in Colmenar Viejo, near Madrid, Spain, Friday, May 2, 2014. The festivity of the Maya comes from pagan rites and dates from the medieval age, appearing in ancient documents, it takes place every year in the beginning of May and celebrates the beginning off the spring. A girl between 7 and 11years is chosen as “Maya” and should sit still, serious, and quiet for a couple of hours in an altar on the street decorated with flowers and plants, afterwards they walk to the church with their family where they attend a ceremony. (Photo by Daniel Ochoa de Olza/AP Photo)

Yasothon resident look on as huge, handmade rockets are launched into the air during the Bun Bang Fai festival on May 11, 2014 in Yasothon, Thailand. During the Bun Bang Fai rocket festival, Thai residents launch enormous home-made rockets into the air to gain Buddhist merit and to celebrate the beginning of the rainy season. (Photo by Taylor Weidman/Getty Images)