Urban planners the world over yearn to replicate the success of Silicon Valley: witness Thames Valley (England) and Silicon Oasis (Dubai), to name just two of these attempts. Invariably, these well-intentioned efforts fail for the simple reason that they’re trying to replicate the wrong model. Silicon Valley is too new, too now, to glean lessons from. Those hoping to launch the world’s next great innovation hub would be better off looking to an older, even more remarkable genius cluster: Renaissance Florence. The Italian city-state produced an explosion of great art and brilliant ideas, the likes of which the world has not seen before or since. This hothouse of innovation offers lessons as relevant and valuable today as they were 500 years ago.