Question

As the army approached the bridge into the city, the commander told them to break step. He did not want the soldiers to march in cadence. Why did the commander give this order?

Answer 1

At a definite point, the bridge would begin oscillating to the matching rhythm as that of the marching footsteps. This oscillation would touch a determined peak when the bridge can no longer tolerate its own power and later collapses. So, soldiers are systematic to break their steps while passing a bridge.