What was the reasson why God sent Jonah to Nineveh and not some other city?

---------- God sent Jonah to prophesy to the Babylonian city of Nineveh, which he did with the greatest of reluctance, thereby effecting the largest mass conversion of a city up to that time. It's possible that Nineveh was a "random" city, but that's probably not the case, given its size and strategic importance. Instead, what made Nineveh significant enough to be chosen in God's eyes? Was Nineveh the "second" city of Babylon, after the capital, in the manner of New York City versus Washington D.C.? Did Nineveh have a "Sodom and Gomorrah" reputation, making it the worst city of Babylon? Was Nineveh unusually open and "cosmopolitan," thereby making it the easiest city to convert? Or was there some other reason that I have overlooked?