At its deepest point the tunnel is 400 feet below ground level and is almost level throughout its length except for a slight gradient to allow for drainage.
It is almost level throughout its length except for a slight gradient to allow for drainage. At its deepest point the tunnel is 400 feet below ground level.
At its deepest point the tunnel is 400 feet below ground level. It is almost level throughout its length except for a slight gradient to allow for drainage.
At its deepest point the tunnel is 400 feet below ground level. It is almost level throughout its length except for a slight gradient to allow for drainage.