In the first level Denial
In the giant monolith, just after the are with all the pots. You'll come across a maze. You should see the silhouetted character in the middle of the room. Now just follow the maze around and walk by all the small statues. These statues will light up as you walk past. Once you've lit up all the ones in the main room, there are 2 doors on the outer wall, one is the door you came from and the other leads to a small room. Go into the 2nd door, It is a dark room with a glowing white character on the other side and a pit in the middle which you need to platform over. The remaining statues will be on these platforms. Once you've crossed and all the statues are lit up you will earn the achievement!