Tourists look at other festival-goers playing in the mud during the Boryeong Mud Festival at Daecheon beach in Boryeong, about 190 km (118 miles) southwest of Seoul, July 19, 2013. About 2 to 3 million domestic and international tourists visit the beach during the annual mud festival, according to the festival organisers. (Photo by Lee Jae-Won/Reuters)

Li Yuming, a local farmer who is interested in scientific invention, works on his unfinished miniature submarine “Xiaguang V” on the outskirts of Wuhan, capital of central China's Hubei province August 24, 2007. “Xiaguang V”, which is 3-metre long, 1.2-metre in height, has a maximum diving depth of 20 metres, and can hold two adults and one child at the same time. The submarine will be used for tour after safety test, local media said. (Photo by Reuters/Stringer)

Maudy – Kalulushi, Zambia. Maudy was born in a hut in a small village close to Kalulushi, in Zambia. She grew up playing in the street with the other children in the village, who all attend the same school, where students ages 3 to 10 years old are in the same class. The village has no shops, restaurants or hotels, and just a few children are lucky enough to have toys. Maudy and her friends found a box full of sunglasses on the street, which quickly became their favorite toys. “Toy Stories” project. (Photo and caption by Gabriele Galimberti)

On August 31, 2012, a long filament of solar material that had been hovering in the sun's atmosphere, the corona, erupted out into space at 4:36 p.m. EDT. The coronal mass ejection, or CME, traveled at over 900 miles per second. The CME did not travel directly toward Earth, but did connect with Earth's magnetic environment, or magnetosphere, causing aurora to appear on the night of Monday, September 3. (Photo by NASA/GSFC/SDO via The Atlantic)

Ukrainian state emblem is seen on a gun's holster as soldiers guard naval base in the village of Novoozernoye, some 91 km west of Crimean capital Simferopol, Ukraine, on Monday, March 3, 2014. Ukraine says Russian forces controlling the strategic region of Crimea are demanding that the crew of two Ukrainian warships in Sevastopol's harbor must surrender. (Photo by Ivan Sekretarev/AP Photo)

A Belgian shrimp fisherman rides a carthorse to haul a net out in the sea to catch shrimps during low tide at the coastal town of Oostduinkerke, Belgium July 3, 2015. At the end of each fishing session, the fishermen and their mounts leave the water to empty the net's contents into two wicker baskets fixed on each side of the horse. This traditional method of catching shrimps along the North Sea coast, which dates back to some 500 years, attracts tourists every summer. In 2013, Unesco recognized shrimp fishing on horseback as an intangible cultural heritage. (Photo by Yves Herman/Reuters)

Dragon boat racers prepare for the fancy dress race on July 5, 2015 in Hong Kong, Hong Kong. The Hong Kong Dragon Boat Carnival will be staged from 3 July 2015 (Friday) to 5 July 2015 (Sunday). The carnival featured two key programmes: the CCB (Asia) Hong Kong International Dragon Boat Races in Victoria Harbour and the San Miguel BeerFest at the UC Centenary Garden in East Tsim Sha Tsui. (Photo by Taylor Weidman/Getty Images for Hong Kong Images)

“Business-class” cabins are seen at First Cabin hotel, which was converted from an old office building, in Tokyo, July 3, 2015. Record tourists to Japan are stretching the ability of hotels to accommodate them in a sector constrained by high costs, forcing developers to think out of the box for means to quickly increase lodging options without breaking the bank. (Photo by Toru Hanai/Reuters)