Shimizu, a Japanese technology company, designed the Green Float concept as “floating cities in the sky” that would be self-sufficient and carbon-negative, allowing mankind to live harmoniously with nature. Each floating cell district has a radius of .62 miles that can house 10,000 to 50,000 people. Joining these districts would form a city of 100,000, and a group of modules would constitute a country. The towers in the center of each district are structured with residences and hospitals at the periphery, offices and commercial facilities in the center, and plants growing along the tower. Carbon dioxide and wastewater from the urban areas become nutrients for the plants, and grains, livestock and fish live along the base and ocean shallows of the tower. Green Float is powered via solar energy, ocean thermal energy conversion and wind and wave technologies, and such cities would be located along the equator where the climate is stable and not prone to hurricanes.