What's required in order to have a city produce "Research"?
In earlier plays through Civ5 I've been able to set a city's production to Research, so I know it's possible, but I've not determined what it is that enables that (in my current game, Research isn't an option from the production menu for any of the cities). What's required (a particular tech, I'm assuming) to make that available?
Solution 1:
Researching Education allows the conversion of Production to Research. (i.e. allows cities to "build" beakers)