When we first enter the Black Armoury and meet Ada she tells us that this place is not meant for Guardians. Now hold on just a damn second, if the Black Armoury is not meant to be visited by guardians, then why the frick is it located in the -blam!-ing tower, literally the place where guardians gather. Secondly, how the -blam!- does a golden age armory exist in the -blam!-ing tower, and we guardians, you know, the ones who own the the tower, not know about this? Like it's literally located a 2 min walk away from the Vanguard Commanders.... How the hell does Spider know about this place in the tower and we don't? How?......
The last city was not built in the middle of an empty field or Forrest. It expanded from an old settlement/village, near wear the traveler finally rested. The section where Zavala and company are currently located was clearly built on old ruins which can be seen farther away from the main section. The vanguard tower, which hosted the main vanguard element and guardians is actually above where we are currently located.