If you are trying to for a mod, follow these steps to ensure they appear correctly in-game:
Use the standard XML format for Galactic Civilizations III. A basic entry looks like this: Galactic_Civilizations_III_Worlds_in_Crisis_v4....
Preserve the site as a museum. (+10 Culture, +1 Diplomacy) If you are trying to for a mod,
Over 12 new planetary events (e.g., "The Artifact," "Space Monsters," "Peacekeepers") that trigger as you colonize. " "Space Monsters