Parts of the Theodorich's supposedly impregnable defense screens collapsed.

Two holes now gaped in the supposedly impregnable steel alloy.

It is 1942, and the supposedly impregnable city is being stormed by Japanese troops.

Although supposedly impregnable, the following list suggests that security still leaves room for improvement!

Its army beat back Israel's superior forces and crossed their supposedly impregnable line of fortifications.

Just over two months later that supposedly impregnable fortress was in Japanese hands.

The uncontested surrender of the supposedly impregnable fort caused a public and political uproar.

It took The Shadow considerable time to open the supposedly impregnable vault.

No one knew who had made this attack on the supposedly impregnable castle.

But if they could take apart a supposedly impregnable vending machine, maybe they could do something here, too.