Whether you agree or not, these Japanese people seem to have mastered the art of engineering and every now and then, they come up with a thing that definitely put the world spellbound and wondered.
Tokyo Wan Aqua-lina or call it Trans-Tokyo Bay Highway is another one of many such engineering marvels that Japanese have came up with in recent times. It is a 15.1 km long marine crossing, joining Kawasaki City in Kangawa Prefacture to Kisarazu City in Chiba prefecture, navigating through the Tokyo Bay. The two areas were otherwise separated by a 100 km journey, passing the heart of metropolitan Tokyo.

The Trans Tokyo Bay Highway not only reduces the journey to just a 15-minute -ride but also helps in reducing Traffic congestions in the broader metropolitan road network.
This modern day marvel passes through 10 km of undersea tunnel on the Kawasaki side with a 5-km-long bridge to the Kisarazu side. Just in case you wanna hang out, there is an artificial island midway and another one where the tunnel and the bridge connects.
The tunnel is claimed to be the largest of all underwater tunnels in the world.