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)

Mary McHugh mourns her slain fiance Sgt. James Regan at “Section 60” of the Arlington National Cemetery May 27, 2007. Regan, a US Army Ranger, was killed by an IED explosion in Iraq. (Photo by John Moore/Getty Images)

A demonstrator runs between burning tires during a curfew, two days after the nationwide anti-government protests turned violent, in Baghdad, Iraq on October 3, 2019. (Photo by Wissm al-Okili/Reuters)

An Iraqi medic takes a nasal swab from a woman in Iraq's central shrine city of Najaf on April 20, 2020, during the nationwide lockdown to stem the spread of the novel coronavirus. (Photo by Haidar Hamdani/AFP Photo)

Iraqi Kurds carry fire torches as they celebrate Nowruz Day, a festival marking the first day of spring, Kurdish and Persian New Year in Akre, Iraq on March 20, 2024. Newroz or Nowruz means “new day” in Persian, and is celebrated to mark the arrival of spring and the first day of the Iranian calendar. It is widely celebrated in Persian and neighboring regions and is recognized on UNESCO's Intangible Cultural Heritage of Human List. (Photo by Ismael Adnan/SOPA Images/Rex Features/Shutterstock)

An Iraqi man sells dried fish ahead of Eid al-Fitr, which marks the end of the Muslim holy fasting month of Ramadan, in Basra on April 8, 2024. (Photo by Hussein Faleh/AFP Photo)