And he gathered them together into a place called in the Hebrew tongue Armageddon.
Revelation 16:16
The word “Armageddon” comes from the Hebrew phrase “Har Meggido”, or the “Mountain of Meggido”. The place known as the Valley of Meggido is well known, but the word “har” does not denote a valley, but a mountain.
Since there is no consensus as to what exactly the “mountain of meggido” is, it is left open to speculation. Whether one group claims it be the same as the valley or other claim it to be a symbolic designation, both are on the basis of interpretation, and there is no “literal” fit for this phrase.
Looking at the timeline of Revelation with Revelation 16 being in the crisis of the third century, this fits in the time of the Goths invading Rome, where they had to cross the Danube river for the Battle of Arbitus. At this battle, the losses inflicted on the Romans were so bad, it had sever consequences on the nation.
It is really a construct of the particular eschatology, which accomplishes quite a few hoops to jump through to arrive at it, to have every possible thing point the same spot, namely the final 3.5 culminating in this battle. It follows a little more logically, if not with a little less “excitement”, that things progress a bit more one after another.
In long and short, the battle at Har Meggido would be well past, some 1800 years ago. No one but popular culture and interpretation requires it to be anything else.