Civilization V is a stunningly enjoyable game which has the potential to inspire people of all ages to learn more about history. Although it does not present an accurate portrayal of historical events (as it allows each player to choose their own path), it presents the course of human history and civilization as a fascinating journey. Even more importantly, the emphasis it places on long-term strategic thinking and planning promotes strong development of decision-making and reasoning skills.
Although the game does not present a specific sense of morality, this ambiguity allows players to think intelligently about the choices they make and the real impact those choices will have on their virtual subjects. This might be lost on younger players, but it's a great idea to talk about this with older, thoughtful children.
In many senses, this game is a lot like chess for the twenty-first century. People play it as entertainment, not to learn, but while playing Civilization V, learning is almost unavoidable, even if you don't notice because you're having too much fun.
Although I rated the game as being appropriate for anybody over the age of 8, that's a reference to the content, not the difficulty. Even on the easiest setting, the game will most likely be too difficult for most children under the age of twelve or so, unless an older player helps them as they learn the game.
The game can be violent in a sense, but roughly in the same sense that chess is violent: in chess, you move pieces from one tile to another on the game board, taking over the territory that your opponent's pieces once occupied. Although the combat in Civilization V is dressed up with fancier graphics and some sound effects, it's relatively abstract like chess, as though you're moving a token on a game board.
In summation, Civilization V is loads of fun, and also a genuinely positive experience, challenging players to engage in creative planning, weighing priorities, calculating risks, adapting to changing scenarios, and considering the morality of their actions. I have been playing the Civilization series of computer games since I was a child, and it took me decades to realize just how much I was learning from it. The beauty is, you don't learn facts - you learn how to *think*, and that's the most important type of learning there is.