The battle of Armageddon is a world conflict, after the third world war known as the war of Ezequiel or the “War of Gog and Magog”, which will take place towards the end of the Great Tribulation, once the Antichrist has broken the peace agreement which he signed at the beginning of the Great Tribulation and he turns against the Jews themselves to destroy Israel. The campaign of Armageddon is described by the Apostle Saint John in the book of the Apocalypse (Apoc. 16, 12-16) which will bring about the Parousia, as Christ in person will return to save Israel from the destruction which the Antichrist will try to inflict on it.
Paradoxically, Christ will return for the second time not being invoked by the Christians but by the Jews, who, seeing themselves cornered by the Antichrist will think: if he who we thought was the Messiah, now betrays us and turns against us to destroy us, lets see if the Messiah is not He who died crucified two thousand years ago. Then, the Jews themselves will cry out to Christ so that he might free them from the destruction, fulfilling the prophecy of the conversion en masse of the Jews to Christianity.
The valley of Armageddon, the plain of Megiddo, to the North of Israel, will be the physical place where the Parousia or the return of Christ will take place. There He will return to defeat the Antichrist “With a puff of His breath”.
After this event, Jesus will ascend the Mount of Olives to execute Judgement on the nations and afterwards to give commencement to His Kingdom in the world.