Siege

Minds protected from new thoughts by ten-foot thick walls.
Ears with the newest selective-blocking systems, ideal for not listening to what you don't want to hear.
A complete arsenal, replete with insults meant to be compliments, maximum strength.
Archers ready at the window-slits, and boiling oil poised over the archways, God forbid any possibilities for change or progress should enter.
And what armour ! Steel-plated breastplates of Certified Good Intentions, and shields of Older Therefore Wiser.
And spears of God Wills It, when nothing of the sort has been indicated by divine communication.
And most important of all, the resolve of It's Always Been Done Just So.

Impregnable.