The Annex was an old off-the-record S.H.I.E.L.D. bunker located in Upstate New York used to store seized weaponry and impounded alien technology. Its entrance was disguised as a regular farm barn.
Interior
When she briefly allied herself with the rogue alien Fifty-One, Veronica Eden and her forces raided The Annex to facilitate him access to the Hydra Supreme Armor. Eden took the chance to outfit herself with devices from Spider-Man's villains. They were tracked down by Fifty-One's former team, the Paladins, who were in turn followed by Iron Man and Captain America. While the Paladins attempted to breach the main door, the two heroes used a side entrance to beat them to Eden and Fifty-One. After obtaining the Hydra Supreme Armor, Fifty-One left Eden to fend for herself. She confronted Iron Man and Captain America, who were then assisted by the Paladins, managing to take her down.[1]