Pics or it didn't happen! It's always been that people tend not to believe something until they see it for themselves. In the 19th century, thousands of New York residents lived in overcrowded tenement slums with crumbling walls, dangerous staircases, and no plumbing. They did piece work in their homes, took in boarders for extra money, and raised so many children some had to sleep outside. Jacob Riis arrived in New York from Denmark in 1870 and had to deal with crushing poverty until he got a job as a journalist with for The New York Tribune. He covered the police beat, and described the conditions in the tenements as best he could, but reading about it wasn't nearly as effective as seeing it. That's why Riis incorporated photography into his reporting. He was a pioneer in flash photography because the tenement apartments were so dark inside. In 1890 he published his book How The Other Half Lives, full of pictures of the poor people of New York.
The book made an impression on the public, but more importantly, on the city's Police Commissioner, a man named Theodore Roosevelt. That's when housing standards began to rise. Read about Jacob Riis and the photographs that brought poverty to light at Danny Dutch.