Secret Vault Solution

At the end of the game there's a secret vault. Here's what you need to open it...

Prerequisites

You need to have collected at least 49 of the "Ancient Relics" throughout the game. The 50th relic is only available after the credits roll and you're able to explore Iraq freely again. Finding all 50 relics will give you the Shadows out of Time achievement.

Important Note About Achievements

You need to have all 50 relics in your inventory to get the "Shadows out of Time" achievement, since you can solve this with 49 out of the 50 relics make sure you have all of them in your inventory before solving the vault. When this puzzle is solved it will remove the relics used and you'll be blocked from getting the achievement, so if you're going to solve it with 49 relics, make sure to pick up all 50 first if you want the achievement.

Solution

The four wall sections each need to have the ancient artifacts put in the correct spot and rotated to the correct orientation. Here's the solution I used (there may be others). Note that each artifact can be either rotated to the right (activating all the spaces orthogonally) or to the left (activating all spaces surrounding it).

Once this is complete, you'll receive the final journal note and (if you collected the other notes in the game) get the "Archivist" achievement.

Interestingly, if you're diligent and get all 49 relics before reaching the vault, you can unlock the cutscene without needing to progress further. This makes the cutscene you see not make any sense chronologically ( why is the ark in Antarctica when Voss hasn't yet installed all the stones? Whose footprints are leading away from the Ark if Locus is still here?) and you can actually see the end credits before beating the last area.

First Wall

11 Relics

Second Wall

11 Relics

Third Wall

13 Relics

Fourth Wall

15 Relics

14 Relics (See note about only using 49 relics)

[Capt. Bollocks]

I think they fixed the achievement so you get the achievement upon obtaining the 49th relic.

The only thing is it doesn't show 100% in your journal as the 50th relic disappears after solving the mural prematurely.

[ROCKWELL]

I think the developers didn't realize that 49 relics could be used to open the vault before the end of the game, otherwise it's completely strange. Because it's basically a grind for the sake of a post-credits scene.

["coreFREAK ㋛]

Thank´s it worked with 49 but you must have 50 before for the Achievment

[Ahoge-dono]

As someone pointed out, it can be done with 49 Relics.

But don't solve this puzzle until you get all 50 first, as it will lock you of the achievement for collecting them.

[Regiseal]

Thank you for this - many puzzles in the game require you to "think like Indy," but this one felt like it was just ripped straight from a moderate-to-difficult puzzle game. I read of others spending 3+ hours trying to figure it out and decided it wasn't worth the time and break in immersion.

[ScottSpork]

The designs with the dots and lines that Indy jots down when he learns a new ancient word kinda reminds me of the designs of these wall puzzles, but I couldn’t find any that matched 1:1.

[TimmyChips]

I just did this puzzle last night and took me a while until I solved it. I wonder if there's some kind of hint on the number of Ancient Relics you have to use for each section, as that was the biggest hurdle for me. I just kind of guessed the number of Relics needed to solve each section would increase to use all 50 relics (so 11, 12, 13, then 14 for each part), but that was a guess.

[Slug Cat]

Last can be done with 1 fewer. So, 49 will be enough.

[Cpt.ButtHurt]

Forth door - 14 relic https://imgur.com/a/M3Uxos5 13 are installed, the 14th has circled the place, because after set this one, will start cutscene.

[CurliestApe2930]

Hey, how'd you manage to get the last one in Sukothai? My map with the Relics shows it being in between the river bank cutscene area at the end of Sukothai and the hidden temple area, but I can't find anything that leads to an area around there. How'd you get it?