During the first scene of Age of Ultron we see that von Strucker's HYDRA base is protected by an electromagnetic shield developed on top of a Chitauri technology.

[blue shield shimmering on the base

The Avengers base seen in Age of Ultron and Endgame isn't significantly bigger than the HYDRA base, so the power footprint of the shield should be about the same (and, the Avengers can use the Arc Reactor technology von Strucker didn't have access to).

Also, Wakanda is protected by a shield of a similar sort, able to withstand Thanos's weapons in Infinity War.

Why is then

the ultimate protection of the Avengers HQ being done with something resembling metal curtains, only, as seen in Endgame?

  • The shield at the Hydra base is based on energy from the Tesseract, not just raw power from an Arc Reactor. The Avengers don't have access to it.
    – Valorum
    Commented May 4, 2019 at 21:33
  • Wakanda is protected by the same kind of a shield though.
    – ximaera
    Commented May 4, 2019 at 23:04
  • 3
    Wakanda aren't in the habit of freely sharing tech
    – Valorum
    Commented May 4, 2019 at 23:05
  • 1
    Was not, before the end of Black Panther. After that, the country was actively collaborating with the Avengers.
    – ximaera
    Commented May 4, 2019 at 23:07
  • 8
    Trying to understand how "science" works in the MCU is a lost cause. It makes more sense if we realize that Hydra, Wakanda, and Tony Stark just have different magic powers and that's why they can't all have the same shields.
    – Adamant
    Commented May 5, 2019 at 0:46

4 Answers 4


The Hydra base in question was anticipating being attacked on a massive scale.

The Avengers had no reason to even suspect that they were going to be attacked.

This is even highlighted in dialog:

NEBULA: They suspected nothing.
THANOS: The arrogant never do.

I realise this only partially applies to the situation, but it also supports that they were completely caught off-guard.

For general safety, they did have the barn-door protocol, which would not just shield the outside from the inside (as they had intended) but also the inside from the outside!

That protocol could have potentially saved them from a huge amount of damage. But the attack they faced was way beyond their anticipation.

  • That isn't really a satisfying answer in my opinion. Tony's entire argument for making Ultron was for potential threats, not threats that he knew of. It seems weird to me that he wouldn't immediately try to copy that technology for his own uses. Commented May 7, 2019 at 15:04
  • 4
    He did have potential threats covered - barndoor protocol. I agree that he would've wanted to use that tech, and he does. In his own suit. I believe he hasn't made a breakthrough yet. Also, Tony's timeline ever since AoU has been very rocky. Civil war broke apart The Avengers, Infinity war broke Tony. By the time of Endgame, Tony hasn't even stepped in the Avengers facility in about 5+ years.
    – Stark07
    Commented May 7, 2019 at 15:26
  • @Parrotmaster: “Tony's entire argument for making Ultron was for potential threats, not threats that he knew of.” Well — based on his Wanda-induced hallucination in Age of Ultron, he was kind of fixated on the Chitauri, having seen their full might in space in The Avengers. A suit of armour surrounding the world seems designed for that sort of threat, when it turned out the real threat was actually the Mind Stone itself. Commented Aug 21, 2019 at 10:04
  • @PaulD.Waite But Ultron already exists when he gets that vision. Commented Aug 21, 2019 at 11:27

The Avengers probably never anticipated a direct attack on their facility. We don’t see one in the MCU

until the last hour of Avengers: Endgame.

The team is generally responding to threats elsewhere; upstate New York seemingly isn’t where bad stuff tends to happen.

The metal curtains in question (the Barn Door Protocol, as described in the movie), was likely designed to keep bad stuff (perhaps an enraged Hulk) in, rather than defend against attacks from outside. The Avengers themselves are there to do that.

  • 1
    TFW someone says bad stuff tends not to happen anywhere New York in MCU.
    – IG_42
    Commented May 5, 2019 at 1:55
  • 2
    @ximaera: that could have been more to keep bad stuff in (perhaps the Hulk?), rather than bad stuff out. It is the Barn Door protocol, referring presumably to the adage of shutting the barn door after the horse has bolted. Commented May 5, 2019 at 11:40
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    @ximaera I doubt that "complicated and expensive" are even words in Tony Stark's vocabulary. Commented May 7, 2019 at 15:05
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    @PaulD.Waite the Avengers facility is also a much bigger target than a domestic house. You'd think Tony with all his premonitions would protect it a bit better, especially with knowledge of Wakandan tech.
    – Ng Oon-Ee
    Commented May 8, 2019 at 3:13
  • 1
    Arguably the base has been successfully infiltrated before in Ant Man, but I don't think Falcon told anyone about that. they do need to be better stock taking though he stole a big piece of equipment without anyone looking into it. Commented May 8, 2019 at 6:55

It might be, just not necessarily on all the time. Maybe they don't want to waste the energy; maybe there's inconvenience in having to raise and lower a shield to go outside.

This may be the case for the Hydra base too, for that matter — in the events of Ultron, Hydra clearly has plenty of warning that the base is under attack.

In any case, the story clearly calls for

the base to be destroyed

... and that could happen with a shield too. It would just take a few more minutes of time to show weapons overcoming it, or

Nebula doing something to bring the shield down.

For something that doesn't really add much, would that extra screen time really be worth it?


The Avengers were probably confident that nobody would dare attack their facility due to their formidable reputation.

  • 4
    Do we have any evidence to believe this is the case? A quote from the films would certainly help your case.
    – Edlothiad
    Commented May 5, 2019 at 7:48
  • Any foe that would avoid attacking Avengers HQ because of their reputation would presumably also avoid attacking Earth for that same reason. And yet...
    – ceejayoz
    Commented May 5, 2019 at 15:28
  • @ceejayoz Well, they're not attacking Earth just for the hell of it, they have some motivation. Destroying the Avengers HQ would only have any impact if you could actually the Avengers, who would have to be inside at the time. Which they're not. So, what benefit would you actually expect from destroying the HQ before invading something actually important or useful?
    – Luaan
    Commented Aug 21, 2019 at 9:52

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