Microsoft founder Bill Gates has made a substantial investment into futuristic toilet technology.
The businessman has splashed out on the bizarre cause in an attempt to improve the world's sanitation by holding the Reinvent the Toilet fair, a US event which challenges inventors to develop environmentally-friendly toilets.
One prototype aims to turn human waste into electricity by using microwave power, and another used urine to flush away waste.
Bill explained: "We couldn't be happier with the response that we've gotten. If we do it right, there's every possibility that some of these designs would also be solutions for rich and middle-income countries."