Achievement
There can only be 500: Survive to 500 population without building a single defensive wall or gate on non-pacifist vanquisher difficulty.
There are two categories in the build menu with gates. The Defense category has walls and gates, which I am sure are affected by this achievement, but what about the fences and gates in the Roads and Fencing category? Will putting these up around your crop fields ruin your chances of getting this achievement? If so, is this intended?