Underneath Tokyo Bay, linking Tokyo to the peninsula of Chiba, is the AquaLine. It is half tunnel and half low lying bridge. In the middle of the AquaLine where the transition from bridge to tunnel takes place is a large concrete car park and restaurant called Umi Hotaru.
From the photo you can see the concrete blocks from the end of the Umi Hotaru and on the horizon the Tokyo skyline. Everything in between is water and tunnel.
This was a set of 5 photos taken between -2 and +2 EV. The sky from the middle exposure photo is overlayed back on the HDR image. It was late in the afternoon when I took this and the concrete blocks are picking up quite a bit of reflection from the sun setting out to the left side of the photo.