This line has since been closed and the tunnel filled in.

The tunnel was long now, and filling with an oily darkness.

With a gesture, he pointed toward the figures, and the tunnel filled with blinding light.

Its mechanical metabolism had used up the rest, and so the tunnel did not simply fill behind him.

Now the tunnel fills with strobe lights and special lighting effects right before each train is launched.

We were just a few yards in front of the tunnel entrance when the tunnel suddenly filled with orange light.

But already the narrow little tunnel was filling with water!

"Do these tunnels ever fill in, or grow back?"

And yet even with so many tunnels filled, the digger city was a vast network of connected chambers.