My friends and I were discussing the possible advantages of the Brandenburg Gate and the issue of city-states was brought up. The rule book defines city-states as "considered to be in the outskirts of the controlling player's capital", so we interpreted this as meaning a city-state cannot be attacked if the controlling player has the Brandenburg Gate. This, to be clear, is because an enemy would have to end its movement on the city-state to attack it. So in other words, any city-state you control is immune to enemy attacks with this wonder. Does anybody else play the Brandenburg Gate this way?