Set Global City Defense to Zero?

[bluefalcon]

What would be the best way to go about setting all cities' defense to zero, i.e. making them capturable by any combat unit without resistance? Should I modify the buildings "Global defense mod" or perhaps just the "defense" value?

 

[Thalassicus]

In addition to deleting all walls/castles/etc you'll need to change the city defense values in the global defines (search for <defines>). You'll also need to remove all policies and wonders that interact with defenses, and create new effects to take their place.