The result of huge urbanization in the late 19th century and the early 20th century lead to huge social divides in cities, prior to government and community efforts to equalize cities.
"There is not a man or a woman or a child in New York who does not owe gratitude for making New York, in every part, so much more fit to live in than it was when he undertook the cleaning of the streets." - Col. George Sanders
Before efforts to clean cities, humans and animal waste ran rampant through the streets, living conditions were atrocities, with poorly lit streets, overcrowded tenant houses, and inflated rates for goods.
Outside of cities, architecture became more complicated and extravagant for the wealthy.
As cities developed, politics and wealth were becoming more and more combined. New York was an example of this, with ferry monopolies for example.