Canal

kinetic bombardment to create canals, 

cheap to carry projectiles inside rockets into space, 

projectiles launched from space towards earth to create crater 

very expensive projects like iranrud canal: 

from caspian sea through iran to persian gulf would be possible 

and less expensive projects like eurasia canal: 

from caspian sea through azerbaijan and georgia to black sea would be economically feasible 

all countries in region would benefit because of increased trade