How did the Medes and Persians conquer ancient Babylon?

The Medes and Persians gained entrance under the walls of ancient Babylon by drying up the river Euphrates and diverting its flow. They then advanced into the city on the dry river bed, causing Babylon to be suddenly destroyed and to fall almost overnight.

Les explains that the Medes and Persians gained entrance under the walls of ancient Babylon by drying up the river Euphrates and diverting it, so they went in on the dry river bed. As a result, the city of Babylon was suddenly destroyed and fell almost overnight. He connects this near fulfillment with the far end-time view, where the worldwide Babylon system of economy, politics, and religion will also come under God's wrath and be suddenly and totally destroyed.

Jeremiah 51:8

Babylon is suddenly fallen and destroyed: howl for her; take balm for her pain, if so be she may be healed.

What is the Babylon of the end times according to this passage?

The end-time Babylon described in Jeremiah 51 is the whole worldwide system of economy, politics, and religion. The passage says it will come under the wrath of God and be suddenly and totally destroyed, just as ancient Babylon fell suddenly after the Medes and Persians diverted the Euphrates.