The collapse of the Babylonian empire is intertwined with the shattering of its gods. When a mighty kingdom falls, the spiritual symbols it trusted in are also brought to ruin. God brings disaster and judgment upon Bel, the central idol of Babylon [מצודת ציון, רד״ק]. As conquering enemies overtake the city, they will smash this idol and strip away the gold that covers it [מצודת דוד, רד״ק, אברבנאל].
A core element of this downfall involves forcing the idol to surrender what it has consumed. The primary approach among commentators is that this represents the vast wealth, gifts, and offerings that the idol worshippers hoarded from other nations. Seizing these treasures serves as ultimate proof that the false god possesses no real power. Alternatively, this consumption represents human lives, referring to the oppressed people and conquered nations who were swallowed up and humiliated under Babylonian rule [רש״י]. A unique Midrashic tradition describes a physical event, noting that the Babylonians placed holy vessels from the Temple, or the High Priest's headplate bearing the name of God, inside the idol's mouth to make it speak. Daniel then approached and removed the holy name, causing the statue to instantly fall and shatter [חומת אנך].
With the idol's powerlessness exposed, the nations of the world will no longer flock to it. In the past, surrounding peoples would show their submission and respect to the Babylonian empire by bringing offerings to its god, gathering and running toward it with the rushing force of river waters flowing into the sea [רש״י, מצודת ציון, רד״ק, אברבנאל]. However, once they realize the idol is completely empty of power, this rushing tide of nations will come to a complete stop [מצודת דוד, שטיינזלץ, אברבנאל].
Ultimately, the destruction reaches the very defenses of the city. Even Babylon's great wall, famous for being exceptionally high, wide, and strongly fortified, will fail to withstand the disaster or provide any shelter for the capital [מצודת דוד, רד״ק, אברבנאל]. While some explain that this massive wall will be actively torn down by the invading enemies [רד״ק], others maintain that it will simply collapse and fall to the earth on its own through a direct decree from God [אברבנאל].