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)

A freediver uses weights, yoga and camera tricks to create the illusion of walking underwater for a film which took three years to shoot and was completed in 2013 in El Hierro, Canary Islands. Like a scene from a Hollywood science-fiction movie, this trick footage shows a man apparently walking on water. The underwater film was shot by biologist Armiche Ramos and brothers Armando and Francisco del Rosario, who used their expertise in freediving to create the illusion. No computer graphics were involved in the production, with the team relying solely on their own skills – and a few hidden secrets. (Photo by Ocean Brothers/Barcroft Media/ABACAPress)

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)

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)

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)

To mark World Water Day, on March 22nd Solidarités International and its agency BDDP Unlimited will roll out a campaign to build awareness of the scourge of undrinkable water.

Foreign tourists join the annual Songkran Festival celebration, the Thai traditional New Year, also known as the water festival in Silom district of Bangkok, Thailand, 13 April 2014. The three-day Songkran Festival runs from 13 to 15 April 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 Narong Sangnak/EPA)