The reason the avengers were assembled in the first place. Once again "The Cache Is Not at the Listed Starting Coordinates!!" This seemed as good a place to start as any. This will lead you to a place that the "Avengers" should be comfortable assembling at. 
It still has the ceiling.
In order to find this cache you must find the members of the "Avengers". These are located in the following caches:
GC4X25C /GC4X4ZM/ GC4X77Z/ GC4X9N8/ GC4XB2J/ GC4XCH6
You are looking for the following heroes: "The Monster" "The Archer" "The Soldier" "The God" "The Spy" "The Knight"
Once you have assembled this team of heroes you can assemble the coordinates and find the cache. AVENGERS ASSEMBLE!!