We recently posted a report of the closing of the last brownstone quarry in the US. Manhattan and Brooklyn have tons of old brownstone buildings, commonly entire blocks of them. Some people like the look and some do not, but it is not a very durable building stone.
I stumbled on this brownstone for sale on the Upper West Side (87th St, just off the Park). If I were a rich guy, I'd enjoy owning a place like this with the top floor used as living quarters for the help. Like most buildings from the era (1850-1910), each brownstone has a garden out back. Looks great from theoutside, but if you look at the video you'll hate what they did inside when converting it to apartments.