I like to see where my ancestors lived in New York City back in the day, and what their homes and neighborhoods look like today.
I've used the New York City tax photos from 1939-1941 to see older views of these buildings. Often I use Google to see the map locations and today's "street views" but now I have a different tool I can use.
Above, a search I conducted on NYCityMap (click here to get started yourself) for my great-grandma Tillie Jacobs Mahler's address in the 1950 US Census. She was in her 90s and living in an apartment with her grown daughter Dora Mahler, who had a chronic heart condition. (Dora was incorrectly listed as "Dorothy" in the 1950 Census.)
At top right you can see I typed in the street address "1933 Marmion Avenue, Bronx." Up popped the correct address and zip code. When I clicked on the address, the map appeared, highlighting this apartment building in a gold rectangle.
Also the column at right of map gave me details such as how many floors (5) and how many residential units (16). The construction year was noted (1921) and an option for "street view" (see arrow on image at top).
Clicking to view the building as it looks today, I saw the apartment building appears very much like it did when Great-Grandma and Great-Aunt Dora lived there. This was a walk-up, no elevator. How Tillie and Dora got up all those stairs, considering their health challenges, I can't imagine.
For comparison, here is the Google Street View version of 1933 Marmion Avenue in the Bronx. Photo taken same month as the other photo, by the way.
Of course, if your New York City ancestor's residence or business has already been torn down, this website won't be of any help. My Dad (Tillie's grandson, Dora's nephew) lived in an apartment at 77 East 109th street in Manhattan as a boy and that address no longer exists, which is why I can't view any building details or photos. He also lived in an apartment at 7 East 105th Street in Manhattan, which was redeveloped in 1921 as some kind of public facility building--no longer a residential building.
Thinking of Dora and Tillie with affection as the anniversaries of their deaths approach. Dora died in June of 1950 at age 55, and Tillie died in June of 1952 at age ... 99 or 100 (maybe).