Rev 16:1

Then I heard a mighty voice shouting from the Temple to the seven angels, "Now go your ways and empty out the seven bowls of God's wrath on the earth."

Rev 16:2

So the first angel left the Temple and poured out his bowl over the earth, and horrible, malignant sores broke out on everyone who had the mark of the beast and who worshiped his statue. (666)

Rev 16:3

Then the second angel poured out his bowl on the sea, and it became like the blood of a corpse. And everything in the sea died.

Rev 16:4

Then the third angel poured out his bowl on the rivers and springs, and they became blood.

Rev 16:5

And I heard the angel who had authority over all water saying, "You are just in sending this judgment, O Holy One, who is and who always was.

Rev 16:6

For your holy people and your prophets have been killed, and their blood was poured out on the earth. So you have given their murderers blood to drink. It is their just reward."

Rev 16:7

And I heard a voice from the altar saying, "Yes, Lord God Almighty, your punishments are true and just."

Rev 16:8

Then the fourth angel poured out his bowl on the sun, causing it to scorch everyone with its fire.

Rev 16:9

Everyone was burned by this blast of heat, and they cursed the name of God, who sent all of these plagues. They did not repent and give him glory.

Rev 16:10

Then the fifth angel poured out his bowl on the throne of the beast, and his kingdom was plunged into darkness. And his subjects ground their teeth in anguish,

Rev 16:11

and they cursed the God of Heaven for their pains and sores. But they refused to repent of all their evil deeds.

Rev 16:12

Then the sixth angel poured out his bowl on the great Euphrates River, and it dried up so that the kings from the east could march their armies westward without hindrance.

Rev 16:13

And I saw three evil spirits that looked like frogs leap from the mouth of the dragon, the beast, and the false prophet.

Rev 16:14

These miracle-working demons caused all the rulers of the world to gather for battle against the Lord on that great judgment day of God Almighty.

Christ again announces His second coming, which He here associates with Armageddon  

Rev 16:15

"Take note: I will come as unexpectedly as a thief! Blessed are all who are watching for me, who keep their robes ready so they will not need to walk naked and ashamed."

And they gathered all the rulers and their armies to a place called [Armageddon] in Hebrew.
Revelation 16:16

Mount of Megiddo on the south side of the valley of Megiddo or Esdraelon southwest of Mount Carmen (2 Chronicles. 35:22; Zecheriah 12:11). Megiddo was the capital of a portion of Canaan that was given to Joshua (Joshua 12:21; 17:11; Judge 1:27). It is at the entrance to a pass across the Carmel mountain range, on the main highway between Asia and Africa, and is the key position between Euphrates and the Nile. It has been the battlefield of many peoples throughout the ages. Thothmes III, the founder of the old Egyptian Empire, said, "Megiddo is worth a thousand cities".

Rev 16:17

Then the seventh angel poured out his bowl into the air. And a mighty shout came from the throne of the Temple in heaven, saying, "It is finished!"

Rev 16:18

Then the thunder crashed and rolled, and lightning flashed. And there was an earthquake greater than ever before in human history.

Rev 16:19

The great city split into three pieces, and cities around the world fell into heaps of rubble. And so God remembered all of Babylon's sins, and he made her drink the cup that was filled with the wine of His fierce wrath.
The mighty city was broken into three parts, and the cities of the nations fell. And God kept in mind mighty Babylon, to make her drain the cup of His furious wrath {and} indignation. (Amp)

The great city—was the capital and seat of the apostate church, the spiritual Babylon. The city in 11:8 is probably different—Jerusalem under Antichrist (the beast). In 11:13 only a tenth of Jerusalem falls, whereas here the city “came to be in three parts” by the “earthquake.”

Rev 16:20

And every island disappeared, and all the mountains were leveled.

Rev 16:21

There was a terrible hailstorm, and hailstones weighing seventy-five pounds  fell from the sky onto the people below. They cursed God because of the hailstorm, which was a very terrible plague.

By the seventh angel... in Revelation 16:17

God remembered all of Babylon's sins, and he made her drink the cup that was filled with the wine of His fierce wrath. (Revelation 16:19)