Rev 16 describes the seven bowls of wrath, and the interval period (Armageddon) of spiritual events between the sixth and seventh bowls (The Three Woes, pg. 66).
“The intervals of all three predicatory schemes (Seals, Trumpets, Bowls) predict historical events which are altogether religious in nature affecting the course of human events. The first interval between the sixth and seventh seals was of the rise of the Christian Church in unprecedented dimensions after the victory over paganism at the time of Constantine. The second interval under the trumpets included several such religious events… The interval between the sixth and seventh bowls predict… gathering all nations to fight against God. Armageddon symbolizes the last and decisive battle in which the enemies named will be overthrown.… Because the design of the book is that the symbols of the intervals have a religious significance more than a secular significance, we must then conclude that the Armageddon symbols signify religious events in a secular context.”
Fred Miller, Revelation: A Panorama of the Gospel Age, Ch. 9, “The Seven Last Plagues.”