A man (2nd L) takes pictures as visitors run away from a wave caused by a tidal bore which surged past a barrier on the banks of Qiantang River, in Hangzhou, Zhejiang province August 14, 2014. (Photo by Reuters/Stringer)

This October 25, 2014 photo provided by the U.S. Geological Survey shows lava flow advancing across the pasture between the Pahoa cemetery and Apa'a Street, engulfing a barbed wire fence, near the town of Pahoa on the Big Island of Hawaii. Dozens of residents in this rural area of Hawaii were placed on alert as flowing lava continued to advance. Authorities on Sunday, October 26, 2014 said lava had advanced about 250 yards since Saturday morning and was moving at the rate of about 10 to 15 yards an hour, consistent with its advancement in recent days. The flow front passed through a predominantly Buddhist cemetery, covering grave sites in the mostly rural region of Puna, and was roughly a half-mile from Pahoa Village Road, the main street of Pahoa. (Photo by AP Photo/U.S. Geological Survey)

Residents wade through flood waters from Tropical Storm Harvey in Beaumont Place, Houston, Texas on August 28, 2017. Houston was still largely paralyzed Monday, and there was no relief in sight from the storm that spun into Texas as a Category 4 hurricane, then parked itself over the Gulf Coast. (Photo by Jonathan Bachman/Reuters)

Stunning images taken by Sean Lenz, 19, and Kristoffer Abligaard, 20, show picturesque waterfalls transformed into vibrant rainbows of colour. The awe-inspiring images were created by clever use of long exposure photography and glow sticks floating through water. Photo: Picturesque waterfalls transformed into rainbows of colour. (Photo by Sean Lenz/Kristoffer Abildgaard)

Growing cities, overuse of fertilizers and factory wastewater have degraded China's water supplies to the extent that half the nation's rivers and lakes are severely polluted. China aims to spend $850 billion to improve filthy water supplies over the next decade, but even such huge outlays may do little to reverse damage caused by decades of pollution and overuse in Beijing's push for rapid economic growth. Photo: Fishermen row a boat in the algae-filled Chaohu Lake in Hefei, Anhui province, June 19, 2009. (Photo by Jianan Yu/Reuters)

A man throws water at pedestrians as residents join in a water-splashing frenzy to honor their patron Saint John the Baptist's Feast Day in San Juan, Metro Manila, Philippines June 24, 2016. San Juan is renowned for its celebration of the Nativity of St. John the Baptist every year of June 24. In a nod to the saint's characteristic act, San Juaneños engage in Basaan (“wetting”), where revellers splash people with water. (Photo by Romeo Ranoco/Reuters)

A schoolgirl is soaked with water thrown by an elephant in a preview of the upcoming Songkran Festival celebration, the Thai traditional New Year, also known as the water festival in the ancient world heritage city of Ayutthaya, Thailand, 11 April 2016. The annual elephant Songkran is held to promote the tourism industry prior the three-day Songkran Festival which starts on 13-15 April annually and is celebrated with splashing water and putting powder on each others faces as a symbolic sign of cleansing and washing away the sins from the old year. (Photo by Diego Azubel/EPA)