The so-called Lilypad Project is perhaps the most fantastical of these green wonders and certainly the farthest from being built but is too amazing a concept not to mention. The idea is to create a series of floating self-sufficient ocean-going eco-city islands. Each one would be able to house 50,000 residents and would support a great deal of biodiversity. Collecting pools located in their centers would gather and filter water for use on board. These would be places for adventurers and refugees alike as water levels rise around the world and threaten many, particularly island, habitats.