Then the second angel sounded: And something like a great mountain burning with fire was thrown into the sea, and a third of the sea became blood. And a third of the living creatures in the sea died, and a third of the ships were destroyed.
Revelation 18:8,9
Mountains in Bible prophecy represent kingdoms so the fall of a kingdom must be in view in the second trumpet.
*This mountain must represent a kingdom that destroyed Jerusalem and persecuted God’s people.
Daniel 9:26 states that ‘the people of the prince’ destroyed Jerusalem the second time in the year AD 70.
Daniel 9:26 states that ‘the people of the prince’ destroyed Jerusalem the second time in the year AD 70.
The prince in Daniel 9 is Christ.
If the prince of verse 26 is Jesus, then the people of the prince must be the Jews (remember that the word ‘people’ throughout Daniel 9 always refers to Israel (see verses 15, 16, 19, 20, 24).
Q: Did the Jews destroy their own city and sanctuary?
Q: Did not Titus and the Romans destroy the city and the temple?
A: Three ideas coalesce in this verse. [1] God used the [2] Roman armies (spoken of as His armies) to destroy [3] those murderers and to burn their city.
A: Three ideas coalesce in this verse. [1] God used the [2] Roman armies (spoken of as His armies) to destroy [3] those murderers and to burn their city.
Behold, I am against thee, O destroying mountain, saith the LORD, which destroyest all the earth: and I will stretch out mine hand upon thee, and roll thee down from the rocks, and will make thee a burnt mountain. Jeremiah 51:25: The prophet Jeremiah compared the kingdom of Babylon with a destroying mountain.
Eventually this destroying mountain became a burning mountain that was thrust into the sea (the passive voice ‘was thrown’ indicates that this is God’s judgment). This is the key verse to understand the second trumpet.
Jeremiah 51:42: The sea has come up over Babylon; she is covered with the multitude of its waves.The waves of the sea destroyed Babylon and made her desolate. In this case, the sea represents the multitude of nations that arose against Babylon and destroyed her.
Revelation 17:15: Then he said to me, The waters which you saw, where the harlot sits, are peoples, multitudes, nations, and tongues.
Since the days of Daniel, four major kingdoms have risen to power and fallen. They are Babylon, Medo-Persia, Greece and Rome. *The power that ruled in the days when John wrote the book of Revelation was Rome.
*Literal Babylon had already fallen when John saw his vision of the trumpets therefore the mountain of the second trumpet cannot refer to the fall of literal Old Testament Babylon.
In Revelation 17, we see a dragon beast with seven heads. However, the heads are actually seven mountains. Each of these heads/mountains represents a kingdom that ruled beginning with Babylon. 
The burning mountain that cast into the sea at the sounding of the second trumpet was the fourth of those mountains or heads of Revelation 17, namely the Roman Empire.
--The Jews in the intertestamental period understood that the Roman Empire was a ‘new Babylon’: “. . . then shall come a great star from heaven into the divine sea, and shall burn up the deep sea and Babylon itself, and the land of Italy on whose account many faithful saints of the Hebrews have perished, and the true people.” Sibylline Oracles, lines 158-161
--1 Peter 5:13: She who is in Babylon, elect together with you, greets you; and so does Mark my son.
Many scholars believe that Babylon in this text is a cryptic reference to Rome. There is persuasive contextual evidence that this is so. God appointed Peter as His messenger to the Jews. Peter wrote his first epistle close to the end of his life and we know that at the end of his life he was in Rome where he would die as a martyr by the hand of Nero.
*Fish--Habakkuk 1:14-15: Why do You make men like fish of the sea, like creeping things that have no ruler over them? They take up all of them with a hook, they catch them in their net, and gather them in their dragnet.--1 Peter 5:13: She who is in Babylon, elect together with you, greets you; and so does Mark my son.
Many scholars believe that Babylon in this text is a cryptic reference to Rome. There is persuasive contextual evidence that this is so. God appointed Peter as His messenger to the Jews. Peter wrote his first epistle close to the end of his life and we know that at the end of his life he was in Rome where he would die as a martyr by the hand of Nero.
Ecclesiastes 9:12: For man also does not know his time: like fish taken in a cruel net, like birds caught in a snare, so the sons of men are snared in an evil time, when it falls suddenly upon them.
*Ships - In Scripture, ships generally refer to trading and commercial prosperity. Ezekiel 27:9, 25, 29: Elders of Gebal and its wise men were in you to caulk your seams; all the ships of the sea and their oarsmen were in you to market your merchandise . . . the ships of Tarshish were carriers of your merchandise. You were filled and very glorious in the midst of the seas . . . All who handle the oar, the mariners, and all the pilots of the sea will come down from their ships and stand on the shore.
--At the sounding of the second trumpet, instead of temporal prosperity, the barbarians invaded the Empire, destroyed the routes of commerce, and decimated the prosperity of Rome.
The judgment of the second trumpet brought the collapse of the entire social and economic order of the Roman Empire.
Gibbon uses this significant language: "Genseric, a name which, in the destruction of the Roman Empire, has deserved an equal rank with the names of Alaric and Attila."