LINK: “(13) And the sixth angel sounded, and I heard a voice from the four horns of the golden altar which is before God, (14) Saying to the sixth angel which had the trumpet, Loose the four angels which are bound in the great river Euphrates. (15) And the four angels were loosed, which were prepared for an hour, and a day, and a month, and a year, for to slay the third part of men. (16) And the number of the army of the horsemen were two hundred thousand thousand: and I heard the number of them.” (Revelation 9:13-16)
There is a legend that four fallen angels (four horsemen of the apocalypse) are imprisoned in the Euphrates, some say under Haditha Dam and that guards have gone mad watching them.
There are others who believe they are under Antarctica and hence all the attention the continent received by the Nazis and today by many countries coming to visit and unusual guests and dignitaries.
This cradle of civilization includes Iran and Syria, two locations in the heart of much strife continually.