There is a small tunnel just below the stone where you can enter.

Such a small tunnel probably meant it wasn't used very often, which suited her just fine.

It was a small tunnel, barely large enough to walk within, but made, not natural.

The line also passed through one small tunnel under a road.

At one point, we found ourselves underground in a small tunnel.

They travel for several days, and come across a small tunnel that has no air current.

In the north wall of the hole was the entrance to a small tunnel.

They are much larger, and barely get through some of the smaller tunnels.

Under any circumstances, he told the others, the small tunnel does not provide a possible exit for us.

A small tunnel opened directly into the side of the mountain.