The richest city in the world
Tyre was the great sea power of its day. Part of the city stood on the coast. Part stood on an island just offshore, protected by water and walls. Its ships traded across the whole Mediterranean.
When Jerusalem fell, Tyre gloated. Ezekiel answered.
The prophecy
"Behold, I come against thee, O Tyre, and I will cause many nations to come up to thee, as the waves of the sea rise up. And they shall break down the walls of Tyre, and destroy the towers thereof: and I will scrape her dust from her, and make her like a smooth rock."
Ezechiel (Ezekiel) 26:3 to 4 · around 586 BC
Then he names the first attacker:
"Behold, I will bring against Tyre Nabuchodonosor, king of Babylon, the king of kings, from the north, with horses, and chariots, and horsemen, and companies, and much people."
Ezechiel (Ezekiel) 26:7
And then a detail that makes no sense, until it happens:
"And they shall destroy thy walls, and pull down thy fine houses: and they shall lay thy stones, and thy timber, and thy dust, in the midst of the waters."
Ezechiel (Ezekiel) 26:12
First came Babylon
Nebuchadnezzar came, just as Ezekiel said. He besieged Tyre for thirteen years (Josephus, Against Apion 1.21). He destroyed the city on the coast. But the island city held out.
Then came Alexander
In 332 BC, more than 250 years later, Alexander the Great arrived. The island refused to surrender.
Alexander had no fleet able to take it. So he built a road through the sea. His men tore down what was left of the old city on the coast and threw its stones, its timber and its rubble into the water, until they had a causeway half a mile long out to the island walls (Arrian, book 2; Diodorus, book 17).
They scraped the old city so clean to get material that it was left like bare rock. Tyre fell.
Stones, timber and dust, laid in the midst of the waters. Ezekiel wrote it down two and a half centuries before anyone thought of building a road across the sea.
Many nations
Ezekiel said nations would come against Tyre like waves. That is exactly how it went: Babylon, then Macedon under Alexander, then others after them, one wave after another.
Why this is a big deal
Throwing a city into the sea is not something anyone does. It isn't a normal way to destroy a place. Ezekiel predicted it anyway, and Alexander the Great did it for his own reasons, never knowing the line had already been written.