Renting a car - that sounds right, thinking back. I think over its history, as the U.S. expanded west, cities gradually became more spread out, and not quite as centralized as those in the general northeast quadrant of the country. The Phoenix metropolitan area may be a good example of that.
Philadelphia is a fascinating city (more interesting to me in many respects to Phoenix). There are board members in that area that live there and lived there longer than I did, so can speak to it better.
In the 1750's Philly was the largest city in the U.S., and the second largest city in the British Empire, behind London. Later the Declaration of Independence was adopted there, and the U.S. Constitution was ratified there as well. Our first two Presidents (George Washington and John Adams) lived and served in Philadelphia while Washington D.C. was being built as well.
So there are parts that have some architectural similarities to parts of Europe, but certainly much has grown and evolved since then as well.