1. Giant meteor/comet
2. Yellowstone super volcano eruption
3. Nuclear war.
4. God
5. Zombies.
This article is about the general concept of Apocalypse. For specific Apocalypses, see Apocalypse (disambiguation).
An apocalypse (Ancient Greek: ἀποκάλυψις apokálypsis, from ἀπό and καλύπτω, literally meaning "an uncovering") is a disclosure of knowledge or revelation. In religious contexts it is usually a disclosure of something hidden, "a vision of heavenly secrets that can make sense of earthly realities".[1]
In the Book of Revelation (Greek: Ἀποκάλυψις Ἰωάννου, Apokalypsis Ioannou – literally, John's Revelation), the last book of the New Testament, the revelation which John receives is that of the ultimate victory of good over evil and the end of the present age, and that is the primary meaning of the term, one that dates to 1175.[2]
Today, the term is commonly used in reference to any prophetic revelation or so-called end time scenario, or to the end of the world in general.
https://en.wikipedia.org/wiki/Apocalypse
So many meanings! That may be why people seem so confused about the topic. What exactly are you talking about?