(building on that) (bolded for clarity)mabellino said:You can "pop rush" production only when you have the "slavery" civic operational. Go to the City screen (double click on the city) and look at the bottom just above where you can emphasise production/gold/food etc.
There are 2 larger buttons that look like a big hammer, the one on the left is the "pop rush" (red vertical arrow)button.
For those who are unaware of the terminology, pop rushing is where you sacrifice citizens to build an improvement/unit a bit faster. It causes increased unhappiness for 10 turns after.
Slave rushing works best when you can increase your population quickly on two food squares. Don't worry about population recovery as you can recover faster with a small population that has a smaller food requirement, than a larger population that ends up covering one food squares.
Every turn you use it increases another ten turns of anger.