It’s difficult to pin down the exact number of buildings in New York City. One source estimates 860,000, another source pins the number at 1,053,713. Whatever the number, we’ll know eventually, thanks to Australian-born James Gulliver Hancock, who has made it his mission to draw every single one of them.

Here’s his story:

When I moved to New York City, I really wanted to get to know Manhattan better, beyond a traditional tourist experience. New York was my new home, and I needed a way to understand it. Drawing every building is my version of a diary of my experience in the city—and it doubles as my own personal map. When I walk by the buildings I’ve drawn, it’s like seeing old friends.

If I’d set out to draw all the best buildings or all the brick ones, I’d wind up having that tourist experience I was trying to avoid. I really like the concept of just all the buildings. By concentrating on the city at large, I get to embrace all the fun buildings between the famous ones, like a crumbling brownstone or that weird falling-apart one I pass every day. Going all out provides me with a more realistic view of the city.

I’m actually not sure how many buildings there are in New York City. The number 900,000 comes up a lot though. I draw, on average, four buildings in a week, so it’s a long-term project to be sure. [Editor’s note: By our tally, this means James is about 1,100 buildings in. Maybe he’ll pick up the pace!]