Risk

To earn this achievement, you need to conquer 7 enemy territories in a single turn. You do not need to conquer all seven in a row with a single force. You can attack from several different locations, so long as the total territories you conquer is more than 7 within one round.

Although you can easily earn this by playing normally, if you want to earn this as fast as possible, create a 2 player game, both as human players. Have the territories assigned automatically to save time. With your enemy human player, every turn, just put all your troops onto a single territory that is out of the way, leaving the rest of your territories with only 1 troop on them. Build up your (player 1) territories with several troops, surrounding many enemy territories with 1 troop, or if you have a path of enemy territories where you can reach all 7 in one path, then simply put all your troops into a single territory and then conquer those 7 in a row, being sure to transfer the max amount of troops to each new territory.