Under water city could fit for 5000 people and draw energy from the sea bed,

Japanese construction firm Shimizu Corp just revealed their new project: An underwater city capable of fitting 5,000 people and draw its energy from the seabed. Shimizu says the project would take five years to build and the technology required would be ready in 15 years.

The structure is divided in three sections: The sphere—just below the surface of the sea—with a diameter of 500 meters (1,640 feet) will house residential zones, business and hotels. The pod is connected to a 15 km (nine miles) long spiral that descends to the earth factory, located on the seabed.

Shimizu hopes this eco-friendly underwater city would attract funds from the Japanese government and private investors. The Guardian writes:

The factory will use micro-organisms to turn carbon dioxide into methane, while power generators located along the ocean spiral will use differences in seawater temperatures to create additional energy – a process known as ocean thermal energy conversion. Desalinated water produced using hydraulic pressure will be pumped into the residential pod.