The Last Judgment, the Christian Day of Reckoning when the dead rise, the seas boil, blood pours from the sky, and other things in the Book of Revelations. It was a popular subject for Art and the Tarot was no exception. What it really is about though, is an end to the world as we know it, a change in the face of everything. Interestingly, an 18th century deck designer by the name of Etteilla divorced this card from its religious roots and called his version of this card simply Chaos.
 
As a literal end of things, this card also represents outcomes, resolutions, and final determinations. Reversed it indicates hesitation and delay.