This is a mod for my Risk Scenario. The point of the mod is making several units trainable at one building, the watch tower. There is one watch tower for each country in the scenario. Also the mod makes this tower building an artefact which can change ownership when a new player's units are close and the old owner is not close. This allows me to use those object to keep track of who owns what country, and who has conquered which country.

http://www.voobly.com/gamemods/mod/155/Risk/Overview