Illuminatiscott
Chieftain
In civIII, i always wished there could be some tile that both boats and units could move through. I know you can do it with cities, but areas like marshlands and such should be navigable to both land units and certain boats. A naturally occuring area such as that would be an absolute center of commerce for the entire world, and such areas occur on earth, as well, e.g. the bosporus straits. Sure you have to get onto a boat to go across, but you can do it in like an hour, certainly not an amount of time accurately reflected with an entire turn in civilization.