Who's This? A haunted island lair.
The facts: When the Justice League of America was first introduced in The Brave and the Bold #28 (March 1960), the premise came complete with a secret HQ, built into a craggy island off the coast of Happy Harbor, Rhode Island. The Justice League would move to an orbital Satellite in Justice League of America #78 (1970), and a bunker in Detroit when it is destroyed (from Justice league of America Annual #2, 1982). Since Who's Who was published, various versions of the League have been housed in embassies, a moon base, the Hall of Justice, and various other satellites. As for the Sanctuary, it was later used by the Doom Patrol (DP v2 #21-35), Young Justice (YJ #1-20), the Reboot Legion (LSH v4 #89-100), and the Justice Society of America (JSofA v3 #34-35). The League did return briefly to the Sanctuary after Infinite Crisis (JLofA v5 #1-29), and the Martian Manhunter built a memorial to fallen heroes inside it in 52 #24.
How you could have heard of it: It's not the most famous JLA HQ - that likely goes to the satellite(s) or Hall of Justice, thanks to a lot of animated material - but the Sanctuary keeps figuring in flashbacks, origin stories, and as a back-up for many teams. Since its later appearances are usually connected to big events, most readers will at least be conscious of the League's original headquarters.
Example story: Secret Origins #46 (December 1989) "Ghosts of Stone" by Grant Morrison, Curt Swan and George Freeman
The story goes back to the first official meeting of the Justice League of America, which surprised me because it starts with empty costume shenanigans, as per JLofA #35 (May 1965). But this seems to be an entirely different instance of the Justice League's costumes going walkabout. Perhaps Morrison is intimating that the earlier story (which involved Dr. Destiny) didn't happen, or happened very differently (beyond the absence of Superman, Wonder Woman and Batman in the post-Crisis's early JLA history). Perhaps it's a tribute that acts as a coincidence. Either way, it seems that it's these possessed uniforms that first draw the League to Happy Harbor.
Of the post-Crisis Core Five, only Aquaman doesn't have a spare costume - though you'd think J'Onn didn't wear clothes at all and simply relied on shape-shifting. Best not think about it too hard. According to J'Onn's mind probe (not the miiiinnnnnd proooooobe!), there's a complex alien intelligence at work and it wants something inside the mountain. The costumes break free of Green Lantern's bubble (the Flash's yellow boots kick through) and Barry tries to find out what's happening by vibrating through the rock wall. At which point, things get very Morrison. There's been this disembodied voice, see, and it's asking someone (the Flash?) to tell their story. And that voice belongs to the mountain itself. Cue the most geological of secret origins:
Apparently, vibrations are the trigger that unlocks memories out of the rock. A stone tape, like in Quatermain? (Morrison's a Brit, so that would be ingrained.) Well, notably, there's an alien landing at the base of the mountain at some point. Barry is spit out of what he calls a silica macrochip, and the alien spirits want the information stored in its stone lattice, which is accessed by sound. Well, the JLA just happens to have a sonic screamer on tap!
The sound unlocks a hologram of the alien landing. The costumes stand at attention. This is a memorial service for the explorers who landed in Happy Harbor a million years ago. Having bonded with the mountain, Flash suggests they should make a headquarters out of it. And the mountain is now witness to a different kind of story.
The Secret Sanctuary now lies empty and sentient - a chilling thought, is Challengers Mountain equally alive? EVERY mountain? - remembering its era of the League whenever some creature skitters across its surface.
That's one way to tell a story about a headquarters - turn into a literal character! (Indeed, that happens twice in this issue!) Still weird, though.
Who's Next? Comics' first super-team.
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