The Fortnite Bat Signal Locations guide shows you where to find the exact locations to complete the challenge to Light up different Bat Signals beyond Gotham City. These are part the Batman-themed Welcome to Gotham City Mission which has just been released for Season 10.
The Welcome to Gotham City Mission is covered in detail. here.
Fortnite Bat Signal Locations
The map shows three locations, all located on the northwest side. There is one east of Pleasant Park in Junk Junction and the last east of Snobby Shores. Simply run up to the bat signal, and press the use button. This will trigger the light that summons the BATMAN and give you credit towards completing this challenge.
Junk Junction Location
This is located in the middle of the area, at the main building.
East of Pleasant Park
This one is located east of Pleasant Park, on the hill just near a tree.
East of Snobby Shores
This one is located on the large hill directly east of Snobby Shores.
This video will help you locate them!