After doing some Math, with 40 turns of 100% Culture Tax our Captial, Vanderbilt, and Sam Walton will be able to reach Legendary Culture. With catherdrals, theaters, and library. I believe this would take about 60 turns to set up, so it would roughly take us 100 turns to complete this CV.
http://nijidraws.tumblr.com/ - Crediting the artist who made my profile pic.