New York City is the most populous city in the United States and the center of the New York metropolitan area. The city has a significant impact on global commerce, finance, media, culture, art, fashion, research, education, and entertainment. As host of the United Nations Headquarters, it is also an important center for international affairs. The city is often referred to as ''New York City'' or the ''City of New York'', to distinguish it from the state of New York, of which it is a part. Located on a large natural harbor on the Atlantic coast of the Northeastern United States, New York City consists of five boroughs: The Bronx, Brooklyn, Manhattan, Queens, and Staten Island. 

Pittsburgh is the second-largest city in the U.S. Commonwealth of Pennsylvania and the county seat of Allegheny County. Regionally, it anchors the largest urban area of Appalachia and the Ohio River Valley, and nationally, it is the 22nd-largest urban area in the United States. The estimated population of the city in 2009 was 311,647, while the seven-county metropolitan area was estimated at 2,354,957. Downtown Pittsburgh retains substantial economic influence, ranking at 25th in the nation for jobs within the urban core and 6th in job density. The characteristic shape of Pittsburgh's central business district is a triangular tract carved by the confluence of the Allegheny and Monongahela rivers, which form the mighty Ohio River. The city features 151 high-rise buildings, 446 bridges, two inclined railways, and a pre-revolutionary fortification. Pittsburgh is known colloquially as "The City of Bridges" and "The Steel City" for its many bridges and former steel manufacturing base.

Chicago is the largest city in the state of Illinois. Its metropolitan area, commonly named "Chicagoland", is the 27th most populous metropolitan area in the world, home to an estimated 9.7 million people spread across the U.S. states of Illinois, Indiana and Wisconsin. Chicago is the county seat of Cook County, the second largest county in the United States by population. The city is renowned for its fascinating museums - including the Art Institute and its expansive collections, including noted Impressionist works; it is a city with an appetite for food, of course, but also for design, history, culture, finance, commerce, industry, technology, telecommunications and transportation.