Having generally employed a heavy military game, I tend to rapidly expand early on through conquest leaving my medival game to be a bit of a clean up before industrial war begins. However, with Civ 5's National Wonders being linked to standard improvements required in all cities, it's rather hard to work them into my game as by the time I get to looking into them the cost of implimenting them vastly outweighs their benefits. Having read up all I can on them, I'm still at a loss as the implimentation of national wonders early on really inhibits my expansion and later on costs more than it's worth. Is there a preffered National Wonder strategy that others have employed? Are they really worth the effort? How the heck can I work them into a military game without having to spend a shed load of gold getting a wonder that will have paid for itself by the time 2050 comes up?