Number One City Data

As I'm winding down this evening on PBS there is Chicago's Loop: A Chicago Tour on PBS WTTW.

It is fascinating!

There is a point (with a plaque!) on a building at LaSalle and Monroe, which is the zero point where all cartographers and surverys measure by in the city. A zero point: I thought I also heard it called number 1 city data.

I'm going to try to find it on my lunch break tomorrow.