The structure combines a main bridge, an undersea tunnel and two artificial islands for border control.

A bridge seems less likely than an undersea tunnel, which would have to exceed 100 kilometres in length.

With an undersea tunnel, the estimated price would drop to $472, a saving of almost 30%.

By segmenting the undersea tunnel, in the event of fire or other disaster the stations provide safety equivalent to that of a much shorter tunnel.

Sage was thrilled by the idea of traveling by an undersea tunnel.

The gorgeous part was the undersea world, its denizens clothed in slippery, silky, almost translucent dark blue and green dresses that eddied around their bodies like water.

There are slight references to water and the undersea world in the video.

She plunges into an undersea world of bizarre creatures and terrifying foes.

Based on rumors he hears from other sailors about the existence of merfolk, he attempts verify these claims by exploring the undersea world with the invention of his primitive submarine.