I don't know if any of this has been suggested or anything so if it has disregard it.

Also I'm not sure if any of this is in the game, I haven't used magic yet.

1.) can we like build walls outside the town, or possibly magically create a wall outside the city, like between mountains or something for an extra layer of defense? so like only flying units can circumvent it, or they are forced to engage it.

2.) and will we have the power to grow forests, plant rivers, deserts and stuff? if we want to?