Underwater ocean floor factory connected to a floating seastead base via a 4000 meter spiral tower

Shimizu corporation is a top 5 construction contracting company in Japan.

They have built terminal 3 of Singapore’s airport and the The Tokyo Bay Aqua-Line aka Trans-Tokyo Bay Highway. Aqualine is a bridge–tunnel combination across Tokyo Bay in Japan. It connects the city of Kawasaki in Kanagawa Prefecture with the city of Kisarazu in Chiba Prefecture, and forms part of National Route 409. With an overall length of 14 km, it includes a 4.4 km bridge and 9.6 km tunnel underneath the bay—the fourth-longest underwater tunnel in the world.

The Ocean Spiral would provide accommodation for 5,000 people and include research centers for excavating the seabed for energy resources.

Previously they have pitched the lunar ring