I just built the Taj Mahal wonder in Civ5 on a normal sized map with normal game speed and Prince difficulty and the game is displaying the Golden Age it just started will last for 21 turns.
21 turns seems incredibly powerful, given that the Golden Ages for great people last (I think) 10 turns to begin with. (And at my current game stage 5 or 6 turns.)
Is this correct or is the gaming displaying a bogus value? (Or would you consider this a balancing bug?)
Addendum: Playing as Washington and I have the Chichen Itza wonder. (Which I conquered, so I wasn't even really aware I had it ;-)