A tower on a rocky outcropping, a powerful bolt of lightning, one or two figures falling from the tower, sometimes waves crashing below.
Basic Tarot Story
As the Fool leaves the throne of the Goat God, he comes upon a Tower, fantastic, magnificent, and familiar. In fact, The Fool, himself, helped build this Tower back when the most important thing to him was making his mark on the world and proving himself better than other men. Inside the Tower, at the top, arrogant men still live, convinced of their rightness. Seeing the Tower again, the Fool feels as if lightning has just flashed across his mind; he thought he'd left that old self behind when he started on this spiritual journey. But he realizes now that he hasn't. He's been seeing himself, like the Tower, like the men inside, as alone and singular and superior, when in fact, he is no such thing. So captured is he by the shock of this insight, that he opens his mouth and releases a SHOUT! And to his astonishment and terror, as if the shout has taken form, a bolt of actual lightning slashes down from the heavens, striking the Tower and sending its residents leaping out into the waters below.
In a moment, it is over. The Tower is rubble, only rocks remaining. Stunned and shaken to the core, the Fool experiences grief, profound fear and disbelief. But also, a strange clarity of vision, as if his inner eye has finally opened. He tore down his resistance to change and sacrifice (Hanged man), then broke free of his fear and preconceptions of death (Death); he dissolved his belief that opposites cannot be merged (Temperance) and shattered the chains of ambition and desire (The Devil). But here and now, he has done what was hardest: destroyed the lies he held about himself. What's left is the bare, absolute truth. On this he can rebuild his soul.
Basic Tarot Meaning
With Mars as its ruling planet, the Tower is a card about war, a war between the structures of lies and the lightning flash of truth. The Tower, as Wang points out, stands for "false concepts and institutions that we take for real." When the Querent gets this card, they can expect to be shaken up, to be blinded by a shocking revelation. It sometimes takes that to see a truth that one refuses to see. Or to bring down beliefs that are so well constructed. What's most important to remember is that the tearing down of this structure, however painful, makes room for something new to be built.
No card scares a Tarot reader like the Tower - or the person they're reading for if that person knows anything about Tarot cards. It is however one of the clearest cards when it comes to meaning. False structures, false institutions, false beliefs are going to come tumbling down, suddenly, violently and all at once. What's important to remember as a tarot reader is that the one you're reading for likely does not know that something is false. Not yet. To the contrary, they probably believe that their lover is being faithful, that their religious beliefs are true and right, that there are no problems in their family structure, that everything is fine at work...oh, and that they're fine. Just fine, really.
Alas, they're about to get a very rude awakening. Shaken up, torn down, blown asunder. And all a reader can really do to soften the blow is assure the Querent that it is for the best. Nothing built on a lie, on falsehoods, can remain standing for long. Better to tear it all down and rebuild on the truth. It is not going to be pleasant or painless or easy, but it will be for the best.