Croatoa Beacon Badge
From City of Heroes: Rebirth - Wiki
Description
You have unlocked the capability of creating a teleport beacon to Croatoa.
How to Get
One earns the Croatoa Beacon supergroup badge by visiting each of the following Croatoa exploration badge locations while in supergroup mode:
Note that visiting these locations while not in supergroup mode will not advance towards earning this beacon badge, even though it will earn the personal exploration badge for that marker.
Location
The Croatoa Beacon location is (161.5, -32, -844), just west of War Witch.