The Lower East Side Tenement Museum at 97 Orchard Street in New York City was once a real tenement. From the time it was built in 1863, 7,000 inhabitants moved in and out of this building. Nearly all were immigrants, poor or working class. Today, each apartment is furnished to represent a different time period. You can step back in time to see how the masses lived, struggling to make ends meet. It's entirely authentic, down to the backyard privies.
I visited the museum look forward to going back. If you live near or in Manhattan, you can attend the many events they hold there.
I'm on their mailing list, and they just sent me an article about the area's crime in the early 20th century, "Returning to the Scene of the Crime". They mention Luc Sante, who wrote LOW LIFE: LURES AND SNARES OF OLD NEW YORK. I read this for research on my 1894 New York novel FROM HERE TO FOURTEENTH STREET which is Book One of my New York Saga.
LOW LIFE is one of the best books I've ever read.
Manhattan's Lower East Side, Early 20th Century