"It is probably the biggest tunnel on the southern border so far."

"It feels like it's a big tunnel or something," I said, trying to keep my voice from shaking.

There are hundreds, perhaps thousands, of big tunnels in Iran.

Amazing piece of work, complete with big tunnel to outside world.

They met only when Tom went to dig his big tunnel.

But to connect the two railroad lines a big tunnel must be constructed.

I found that it is really a big curved tunnel.

Then we start climbing if the tunnel's big enough.

I try to watch the work going on out in the big tunnel.

"Found a bigger tunnel, leads down and straight ahead for several hundred meters."