I have no idea when they added it, but Google Street View now has a time travel feature. There's been tons of construction in my area since I moved here, so it's pretty cool to see parking lots turn into high rises. When I discovered this feature, I became excited to think that in 50 years I'll be able to look back (hopefully) and see the transformation of our society in time lapse. Imagine if we had a street view from 400 years back. Cool stuff!

But what if Google removes this service? We don't have a backup.

The Welikia project is a great resource, but it bears mentioning that it is focused on the island of Manhattan and hasn't yet expanded to NYC's other boroughs.

Indeed, and I totally understand why most people think of Manhattan as being "NYC" but it's a pity the rest of it is not considered in analysis like this one (or at least why only Manhattan-centric stuff is reported). There are so many beautiful places in other boroughs, dunno why only the skyscrapers get the credit :-)

The article mentions that the project is working on expanding to the other boroughs. They just finished Manhattan first.

We changed the title to say Manhattan instead of NYC.

What every block of Manhattan looked like 400 years ago