On Mission 6 "Zurn Valley", destroy 50 objects and vehicles without dying to unlock this achievement. It is recommended that you do not attempt this achievement on hard.
Destroyable objects are:
Large Oil Silos
This will pop in game if you get it. Mine popped before the final helicopter fight. If you do not get it, just replay the level on easy. Mine did not pop when selecting restarted chapter in game. I had to go back to the main menu and re-select the mission there.