Final answer:
The city that had a 12-day transit worker strike causing the subway to shut down was New York City.
Step-by-step explanation:
The popular city in the North East that experienced a 12-day transit worker strike leading to a subway shutdown was New York City. This incident is an example of the struggles between labor forces and management that have occurred throughout history in various industries, including transportation. In the case of New York City, disruptions like these highlight the importance and impact of transit workers in urban settings, reflecting the ongoing challenges in worker organization and the pursuit of better working conditions and wages.