Must see: Plans released for underwater city that could house 5,000 people

Ocean Spiral is the name of Shimizu Corp.'s newly-revealed plan for an underwater city that could house up to 5,000 people.

The design centers around a floating, 500-meter-wide sphere linked to a resource center on the ocean floor via a 15-kilometer, helix-shaped path. 

According to The Guardian, the central dome would house business and residential zones.

At the base of the Ocean Spiral, researchers will explore and research ways to excavate resources from the seabed. 

Shimizu Corp., a Japanese construction company, claims that the project is realistic, and that the technology needed to make it possible will be available within 15 years.