There are five pillars of Nazi propaganda that are to be destroyed for this Achievement. They are grey statues with golden eagles on the top.
Entering the ruined city, the first will be just beyond the motor pool that you can take over. Blow a hole in the wall and it will be on the left side. The second is at the bottom of the hill to your right.
The third tower is on the way to the church, and the fourth is in a cul-de-sac directly opposite the church.
The fifth tower is the easiest to miss - stand next to the church and look back toward where you came, to the right of the cul-de-sac where you found the fourth statue. You may see the eagle poking out over the top of the wall. Blast a hole in the wall and you'll easily take down the last statue.
The Achievement will unlock as soon as the fifth statue falls.