Fish Tank Achievement
Send the tank into the river by blowing up the bridgeDuring Mission 3, 'Kaiser-Friedrich Museum', you will have to place two explosives on the supports of a bridge. Once that is done, follow the objective marker to set up at a vantage point facing the bridge. Eventually you will see a few enemies and three tanks attempt to cross the bridge. Don't let them cross! Wait until the first tank reaches the bomb then snipe it to unlock this achievement. If you miss or don’t unlock the achievement, reload the checkpoint.
Thanks to 360GameTV for the video: