A simple, low-cost filtering invention has earned Tanzanian chemical engineer, Askwar Hilonga the Royal Academy of Engineering African innovation prize.

'A'Gua water bottles by Donald Thomson are custom-designed plastic water bottles that turn into roofing tiles when empty.

The visually impaired take photos too, says Dustin Adams, the designer of VizSnap.

Designed to be self-administered and cost only one dollar, this contraceptive is changing the state of women's health in developing countries.