Strange behavior of see serpant.
When you select see serpant and try to move him to not coastal city, game is frozen for few(2-5) seconds. In the end the path is calculated and it seems you can move to city.
http://imageshack.us/photo/my-images/7/seeserpant.jpg
I think this path calculation can use pretty much of server cpu time.
My guess is that see serpant has ability to move in water, swamp and city but path calculation at the begging don't know if the city is coastal or not, so path calc start to calc path.
Solution: Every city would have boolean flag that says if it is coustal or not and in path_calc method will be if clause to ask it.
EDIT: Posted link to image, because image tag is not working for me. What Am I doing wrong?