Adam Clarke on Jeremiah 51:58

The broad walls of Babylon - Herodotus, who saw these walls, says, "The city was a regular square, each side of which was one hand red and twenty stadia, the circumference four hundred and eighty stadia. It was surrounded by a wall fifty cubits broad, and two hundred cubits high; and each side had twenty-five brazen gates." - Herod. lib. 1 c. 178. Had not Cyrus resorted to stratagem, humanly speaking, he could not have taken this city. For the destruction of this wall and its very vestiges, see on Isa 13:19 (note).