row 1, Riddle 1
Just scan the top of Wonder Tower.
row 1, Riddle 2
Looking at the front door of the museum, head right and follow the wall. By the ramp leading to the subway, on the wall of the museum, you should see Wanted Posters for Bruce Wayne. There will be a bunch of them. Scan them.
row 2, Riddle 1
From riddle 3/1, standing in front of the hat shop, head east and then head north at the next corner. Once you go over a small bridge, turn left and you should see Sal Maroni's Italian Restaurant. Scan the sign. This is attached to the same same building as the Hat Shop as far as the map is concerned.
row 2, Riddle 2
From riddle 2/1, starting at Sal Maroni's Restaurant, head north until you hit the corner of the building. Turn east and look down to street level and you will see a shop that sells puppets and magic props. Scan the sign of the puppet.
row 3, Riddle 1
Standing on the Museum and looking east, you should see a lit up sign for "Live Nudes." Just to the right and under that sign is a "Hat Shop" sign. You can scan it from here if you zoom in.
row 3, Riddle 2
Along the southern wall of the city, on the street closest to the Restricted Area, you will find a news van. South of the news van, blocking the road access to the rest of Gotham is a door with the TYGER symbol and says "Inmate Behavioral Analysis Unit."
row 4, Riddle 1
East of "The Bowery" on the map, you'll see two buildings connected by a small bridge on the map. On the roof of the northern building will be a billboard with Quincy Sharp on it. It will be on the southern part of the building.
row 4, Riddle 2
Keep heading through Wonder Tower until you get to the courtyard with the giant Dr. Strange TV broadcast. There is a door to the left of the giant TV and inside is the guard that you may remember from the AC trailer. Scan his body.
row 5, Riddle 1
Go into Wonder Tower from the Bowery. This requires you to hack the door on the second floor with the TYGER encryption (as you would during the story). Go through that door and up the hall to the next which you have to open with the REC. On the other side, instead of dropping down, go to the gate on the opposite side of this level. You will need to hack a panel inside the room beyond to open the gate which will require the Sequencer upgrade. Open the door and look through the first window. Activate detective mode and you should see the dot on the window sill in this room and the rest of the mark on the window on the far side. Line them up.
row 5, Riddle 2
On the balcony just before the door you hack to enter Wonder Tower, there is a plaque. Go to the south end of the balcony and you will see a plaque that reads "Arkham City Opened by Mayor Quincy Sharp On the Novermber 19th, 1..." and the corner of the sign is broken. Scan the sign (may need to zoom in).
row 5, Riddle 3
Go down to the street just to the east of the Museum. Head north up the street but watch out for mines. When you get to the last section that is still under the roof, look towards the gate to the north. Up above the gate is a sign advertising "Sale On! Crazy Prices!" Scan that sign (may need to zoom in).