Just entered IA a few weeks ago and I'm considering my wonder options for this age (I'm a conservative/defensive/saver player). The Eiffel Tower Wonder "provides a peace treaty once a week." Are these treaties "save-able?" That is, can one accumulate them and use them when one wants? Or do they just kick in automatically once a week beginning with when the Tower is complete and the player has no control re timing of use? Thanks in advance for your help.