Start a mission in Freeplay mode on difficulty Easy.
For anyone that just likes a simple map instead of a video like I do, see below. The districts are the gold text areas, the hidden places are the arch icons, and the landmarks are the binocular icons. For the landmarks in game, there should be glowing orbs to highlight a document to pick up. For the other locations you can pretty much just fly in and it will count.
Happy hunting!