Peter and Minke van Wingerden developed a floating cow farm in the port city of Rotterdam, where land is scarce and climate change is a daily threat. The three-story farm floats can adjust to rising sea levels. The cows live on the top floor, while their milk is processed into cheese, yogurt and butter in the middle layer. The cows' feed includes grain from a local brewery and grass from local golf courses. Their manure is turned into garden pellets and their urine is purified and recycled into drinking water for the cows. Solar panels produce enough electricity for the farm's needs.