Looking through the World Builder I found out that it's possible to enable Permanent Alliances. I used this feature to enable sort of a "European Union" in late game. I didn't have enough time to test it out, but I was wondering if anyone has answers for some questions this raised: How does stability behave once Permanent Alliances are enabled? What about respawns and collapses, do they break/resume the alliance? And how does the fact that civs have different tech costs translate into Permanent Alliances (since normally the tech cost and beakers are shared in a pretty simple manner)?