A suggestion: each country has a national monument.
For example, for France, this may be the Eiffel Tower.
A monument is an object that the presidents can deposit in a region of their choice, in a round of their choice, as a defense system.
The monument gives 30% defense bonus and can couple with another defense system.
If the round is won by the attacking country, this one wins the monument. This monument may be either returned to the loser country for free, or resold to the loser against a ransom of 300g , either the winner can keep it and install it on one of its regions.
On the country page, we can see the monuments he has .
Translated with Google