I've wondered this for a while and never found a satisfactory answer. Free buildings, of course, are free - no build time, no build cost, no maintenance. However, what happens if the city in question already has said free building? Specifically, the CN Tower is available MUCH later than the Broadcast Tower. When I finish my CN tower, do all the Broadcast Towers I've already built revert to their free, no-maintenance versions? Or would I have to refrain from building ANY Broadcast Towers until near-endgame in order to maximize my benefit from this particular wonder?

The same question applies to other "free building" effects - Great Library (Library), Hubble Space Telescope (Spaceship Factory), Legalism (Monument), completed Tradition culture track (Aqueduct)...

  • Note that you can deconstruct any normal building in a city's building list if it has a maintenance cost.
    – Samthere
    Mar 20, 2013 at 16:48

2 Answers 2


For Legalism, if a city would get a free culture building but already has built all researched ones, it will get the next culture building once it is researched.

I was curious about this, so today I started a game, built Monument in my capital, and took Legalism. The Monument still cost maintenance, but as soon as I was able to build Amphitheater, a free one popped up in my capital.


They do change into no maintenance version.


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