Women sing and dance as children gather in the background during the so-called parade of children's troops in Rostov-on-Don, southern Russia, May 14, 2015. About 500 children aged from 4 to 10, members of youth military patriotic clubs, honor guards and paratroopers took part in the event, which was organized under the guidance of Commander of Southern Military District Colonel-General Alexander Galkin and was held to honor World War Two veterans and mark the 70th anniversary of the victory over Nazi Germany, according to local media. (Photo by Eduard Korniyenko/Reuters)

A combination picture shows Will Adam, 14, snowboarding down a street on Beacon Hill during a large winter blizzard in Boston, Massachusetts, United States January 27, 2015 (top), and a woman looking at her phone as she walks down the same street June 13, 2015. Outdoor scenes in Boston show local residents enjoying balmy weather amid lush greenery as the summer solstice approaches on 21 June. The very same locations suffered heavy snowstorms last winter, with snow ploughs, skiers and snowboarders battling the drifts. Boston got 275.8 cm of snow over the winter, the most since 1872, when records began. A few months after the snowstorms, Brian Snyder revisited the same places and shot pictures at exactly the same locations. (Photo by Brian Snyder/Reuters)

In this August 3, 2015, photo, residents make their way through floodwaters in Minbu, Magway division, in Myanmar. The Ministry of Social Welfare, Relief and Resettlement said that more than 200,000 people are affected in 11 of the country's 14 states and divisions by flooding. In addition to damage to houses and farmland, infrastructure has been very badly hit, with roads and rail lines cut in many places and telecommunication links broken. (Photo by Hkun Lat/AP Photo)

In this May 14, 2016 photo, children wearing their school backpacks climb on a cliff using a bamboo ladder on their way home from school in Zhaojue county, southwest China's Sichuan province. A village in China's mountainous west where schoolchildren must climb an 800-meter (2,625-foot)-high bamboo ladder secured to a sheer cliff face may get a set of steel stairs to improve it's safety. (Photo by Chinatopix via AP Photo)

Long-tailed mayflies (Palingenia longicauda) mate on the surface of the Tisza river near Tiszakurt, Hungary, June 14, 2016. Millions of these short-lived mayflies engage in a frantic rush to mate and reproduce before they perish in just a few hours during “Tiszaviragzas” or Tisza blooming season from late spring to early summer every year. (Photo by Laszlo Balogh/Reuters)

In this Friday, February 5, 2016 picture, Egyptian farmer Ahmed Ayman, 14, rides his trained donkey as he jumps over a barrier in the Nile Delta village of Al-Arid about 150 kilometers north of Cairo, Egypt. He discovered the donkey's talent after she jumped over a small irrigation canal. (Photo by Amr Nabil/AP Photo)

A figure of a skeleton is seen painted in a hallway of the house built underground by Manuel Barrantes in San Isidro de Perez Zeledon, Costa Rica, March 14, 2016. Barrantes started digging through red soil and volcanic rock on his farm 12 years ago to build his subterranean house, between 15 and 63 feet (4.57 and 19.2m) underground. The dwelling, which Barrantes says provides a peaceful and comfortable home for him and his family away from noise pollution and the effects of climate change, now covers about 2,000 square feet (185.8 square metres). (Photo by Juan Carlos Ulate/Reuters)

A Thai visitor appears to be frightened by a life-size Velociraptor model also known as Raptor at the Dinosaur Planet theme park in Bangkok, Thailand, 25 March 2016. The 500 million baht (14 million US dollars or 12 million euro) theme park opening in the Thai capital aimed to attract more than 15,000 visitors a day featuring a chance to experience more than 200 dinosaurs from various species that are brought back to life. (Photo by Rungroj Yongrit/EPA)