South Park: The Stick of Truth -Parkeologist Achievement

Achievement - Parkeologist
Open all garages in South Park.

Every house in the neighborhood has a garage. Some can be opened straight away, others require you to find a key. The key is normally looted from inside the house itself, if the garage is locked. The earliest you can unlock this achievement is after the main story takes you to Kyle's backyard. Once there, you now have access to loot his house and find his garage key. His garage is the last one you can open. Also, storage units need not be opened for this achievement.

Three other garages of note:
1. Jimmy's garage key must be looted inside his house either during the story quest or afterwards, from the hallway outside the bedrooms
2. The garage on the house next to Mr Slave's only cracks open partially (need shrink ability to enter), but this counts as it being opened
3. Don't forget about Token's house, since it is set back away from the rest of the residential area