civmademepoor
Chieftain
A thought I had while reading over the suggestions, all of which I like in their various ways, but to me they seem primarily medieval/early Renaissance, particularly as we parse it down. I think much of the game, especially for the late spawners, really starts to take off in the 16th and 17th centuries, so some things like the Globe theatre, Wren's St. Paul's (maybe allow a no anarchy revolution?), JS Bach's cathedral, Newton's college, hopefully buildable for Genoa, Austria, Moscow, the Turks, etc. . ., if not Holland and Sweden.