five-block radius

[Mike Hussey]

CRONIN: Pam, I want to show you something. It's in Alexanderplatz. We got three levels, we got 15 tunnels. They're all converging in a five-block radius.

What does "five-block radius" mean?

Source: The Bourne Supremacy (a 2004 American action-thriller film featuring Robert Ludlum's Jason Bourne character)

 

[Raymott]

Do you understand what a city block is? It's the area enclosed by four intersecting main streets (like this #), not counting alleyways or lanes.
A five-block radius is a radius of five blocks. From the centre in Alexanderplatz, you measure five blocks, then draw a circle around the centre, the circumference of which will be 5 blocks to the north, east, south, and west of the centre. The diameter will be ten blocks. That's how far the tunnels extend.