So I found on the other topics how to use the slavery button. I have Bronze working research. So I should have Slavery. But on my cities I can't activate the "Slavery" button it still says "Slavery needed", so my guess is that I should activate it somewhere... But how do I do that?
I should have enough population to use Slavery btw (I have +9 angry people for overcrowding in the city I want to use it).
When you first research Bronze Working (and other techs that unlock new Civics), a popup screen will appear to allow you to switch to it immediately. If you choose not to do so, you can access the Civics menu by pressing F3. --- Xiahou Mao, True Hero of the Three Kingdoms!
Are you sure you actually changed Civics and didn't just select Slavery then exit without clicking "Begin Revolution"?
Also note that you can only sacrifice at most half of a city's population at a time, so for larger buildings you might not have the population necessary. --- "Est Sularus oth Mithas...'My honor is my life.' You are your father all over again." -Tanis Half-elven, Dragons of Summer Flame
Yes I did do the revolution. But didn't know about the max population thingy. Apparently that was the reason, I just tried it on a city with less days left for the building it was making, and the button wasn't grayed out :). Thanks for the info ! Really helped me out... I twas frustrating to not be able to use that function.