Paul Sahner has been documenting New York, block by block, on his photographic blog NYC Grid for only a few months, but has already amassed a fascinating portrait of the city.

One interesting task he set himself recently was to re-photograph locations originally captured by his grandfather in 1961. Looking at these photographs side-by-side is revelaing, both in how much and how little some things have changed. It’s a nice little reminder that the world of Mad Men wasn’t actually that long ago, and that dramatic shifts in society have occurred in and around the the stubbornly unchanging monoliths of New York architecture.