AC Brotherhood Romulus Lair Locations

[BrandyChoate]

Ok, so 1st time using this forum because I am stuck... I need to find all 6 of the Romulus Keys... I have 4 now but I am unsure exactly which 'lairs' they vame from... Is there a way to see which of the lairs have already been completed? Also, on the map when I set the display to show the Romulus Lairs it shows : Romulus Treasure ( where I go once all keys are found), 2 Lairs of Romulus, 1 by the Vatican & the other in the Antico District south of the Colloseum... So that is 2... The other places it shows is the "Barracks", the 'Rosa in Fiore" & the "Thieves Guild".... Are there lairs inside these places somewhere? I have been all over these buildings and can find nothing... Please help...
Also, in one of the Lairs, this is the one which looks like you are inside a bombed out church, chandaliers hanging from ceilings, I can not find my way through... There are several rooms on the 'ground' floor, but it looks as if I need to go upstairs and I am unable to find my way!!! Please help!! This one is driving me crazy!!!
I am on Memory 9 and before I go any further I would really like to complete these mini-missions, or what ever they are called....
Thanks for any help that can be given

[SixKeys]

Once you have completed a lair, the wolf icon for that one disappears from your map, that's how you know you've completed it. There's one lair that you gain access to only after renovating all the aqueducts. That one (Terme di Diocleziano) is well-hidden and can be frustrating to enter. The entrance to it is inside a brick wall, above a pool of water surrounded by some pillars. You can access it by hanging from the ledge right above the entrance, dropping down and catching yourself right before plunging into the water.

If you can't find your way through the lairs, look up a playthrough on YouTube. There are individual walkthroughs for each one. The one you're describing sounds like "The Sixth Day" (I believe that was the name).