The answer is: Haran

Gen 10:8-10

While Haran isn't mentioned as part of Nimrod's kingdom, it had significant importance in biblical narratives, especially surrounding the Patriarchs. Given that Nimrod is depicted as a mighty hunter and king in the land of Shinar (which likely corresponds to Mesopotamia), cities like Babel, Erech, and Accad were pivotal to his dominion.

Genesis 10:8-10 tells us that Nimrod had a bold, larger-than-life personality, and he is sometimes viewed as a precursor to tyrannical figures throughout history. He built Babel, infamous for the Tower of Babel story, which symbolizes humanity’s desire to reach the heavens and its subsequent scattering by divine intervention. Fascinatingly, many ancient cultures have their own versions of a "great tower" that reached to the gods—something scholars suggest mirrors the universal myth surrounding human hubris.

Haran, as an important trading outpost much later in history, becomes the place where Abraham’s family begins their transformative journey. Interestingly, the name "Haran" means "road" or "crossroad" in Hebrew, which is symbolic of a new phase in history as people changed paths and faiths.

Overall, while Nimrod’s kingdom was about powerful cities and exceptional might, Haran stands apart as a place of transition. It highlights that not all significant cities thrive within the grand schemes of kings, yet each plays a vital role in the unfolding narrative of faith and civilization.