Need Gizeh Postcard item in Castel Sant'angelo

[abigor]

I've finished the main game and have one last field note showing for Castel, which appears to be inside the larger structure. I travelled back here from the Vatican but the area that the map shows the collectible in I can't seem to get to.
WTs show it as in a barracks that I would have gone through at the beginning of the game when I had no idea I was looking for all of these things, and I've been wandering around trying to access the area I need with no luck.

Someone please let me know if there's an access point I'm missing? I'm beyond frustrated.

TIA

[Camzillasmom]

It is near the gate you have to open to get up to the zipline that takes you down. in this road, where the gate is, look for a staircase up to the captains quarters (there is a sign as well). up there is a room with bunkbeds where the card is

[abigor]

Originally posted by Camzillasmom:

It is near the gate you have to open to get up to the zipline that takes you down. in this road, where the gate is, look for a staircase up to the captains quarters (there is a sign as well). up there is a room with bunkbeds where the card is

Thanks - I didn't realize that I could climb up the scaffolding into the building, which was my problem. Once I got up there, I was able to find the postcard and solve the Bulls of Blood quest too. The white paint showing me I could climb higher wasn't obvious, which was where I was going wrong. Now I'm after the last three field notes!