Now the seven "bowls of wrath" are released. Notice, as we have noted before, that there were seven seals, seven trumpets and now seven bowls. Each of these is an escalation and spiraling of the one before it. Notice also that the river turning to blood, frogs, and hail stones from the heavens call to mind the plagues that God visited upon Egypt in the book of Exodus. Later (16:19) the punishment is specifically poured out on "Babylon the Great."
The one other curiosity here is the mention of Armageddon (16). The word in Hebrew literally translates; "The Hill of Megiddo". The hill of Megiddo defends the pass from the via maris through the Carmel Range. Large armies and groups must pass this way from the powers of the North (Assyria, Babylon, Greece, Rome) and the powers of the South (Egypt). To the west is the Mediterranean sea (cannot pass there) and to the East is the great Arabian Desert (cannot move large groups of people there). It has been suggested that whoever controls the hill of Megiddo controls all of the traffic from the North and the South. In all of Israel's history they have controlled that hill for less than 100 years -- the 40+ years under David and Solomon and since 1948. Major battles were fought over that sight and fortresses on that Hill are dated back to pre Canaan times. For the Hebrew psyche this hill has always been a place of battles and decisive battles. If John is going to call up an image that depicts war and fierce battles it has to be Armageddon. The illusion may have been lost on the modern world but John's first readers would have immediately known what he was writing about.