Untreated sewage leads to poor sanitation and disease around the world. Its effects are strongly felt in India, and Bangalore resident Tharun Kuman turned to cows for a solution. With help from the Biomimicry Institute, he has designed and built 50 sustainable sewage plants that work in a similar way to a cow’s stomach. The system has no moving parts, so it doesn’t require power or people to operate it. The team plans to export the design to Africa. Imagine that -- cows helping to solve the world’s sewage problem.