The Players' Guide to the Cities/User Interface/Clues Window
Depending on the mission, you may need to unearth clues to keep the narrative moving forward. Each time you obtain a new clue, it flashes on the screen and may then be accessed in the "Clues" tab. In this tab is a list of clues you have discovered in the course of your adventures.
Clues provide valuable information that might come in handy for your contact or might point you to the next step in your current mission. This is the key in many cases, as you need to find all clues to fully complete a given mission.
On occasion, certain clues might persist after you've seemingly completed all tasks related to that mission. In that case, the chances are near 100% that there's something you have yet to do that relates directly to that clue--this is why it's important to read all of them when you get them!
Souvenirs are clues you are allowed to keep which provide a historical account of any story arcs you have previously completed. In the "Souvenirs" tab of this window, you will see a list of all the souvenirs you have collected. To view the details of any of these souvenirs, click the ">>" button in the lower right to expand the souvenir's information. To collapse the entry again, click on the "<<" button in the lower right.
Architect Souvenirs are received when you complete a mission in the Architect Entertainment system. They are available to all characters of the global handle which completed the story.