From swimming pools to glacial lakes, clean water is essential and plays such a large role in our lives. That really showed through in all the great photos that were submitted for last week's challenge.
Mashable launched this challenge in partnership with PepsiCo to celebrate its sustainability microsite #HowWillWe, where you can learn more about smart and sustainable ideas. Submitted photos used water as the subject, as a lighting tool and even as a mirror. Below, take a look at our favorite #MashPics_CleanWater entries.