- A "red" flash symbol over a Block means it is available for you to unlock.  Keep in mind, entering a Block for the first time will trigger a fight with whoever is located inside!  

- A "green" symbol represents a Neutral Gang invasion.  After a Block is unlocked, Neutral Gangs will sometimes invade the area.  Once occupied, you'll be unable to enter the Block again until you have removed the enemies.

- A "blue" symbol represents an invasion of "elite" Gangsters.  This is the same as a Neutral Gang invasion, but these enemies are much tougher.

- A Player's "Avatar" symbol means that another Player has invaded and occupied the territory.  Unless you are strong enough to remove them from the area, they will maintain control for up to 72 hours and collect any Cash or Resources produced during that time.