The U.S. military has developed several different weapons to attack these underground fortresses.

He met a Political Officer on the way, near the en- trance to the underground fortress.

The house contained the entrance to the super-mutant's underground fortress.

If only they would succeed now in penetrating the underground fortress- Tatjana didn't waste any time.

They were standing near the entrance to the underground fortress.

The warren was the Vani's best asset, an underground fortress the gnolls would find hard to break.

They were delighted to be living in the open air, instead of in an underground fortress.

The magician then abducts the tiny Princess and takes her to his underground fortress.

Five of them sitting about a table in the dungeons of an underground fortress near Washington.

Combined with Dennis the two attempt to find Liv in the underground fortress.