Answer:
Explain everything. Imagine that the person who was asking, knows nothing at all so you need to start from the very beginning.
Explanation:
In my personal opinion, I believe the most powerful act he did was forcing the nobles move. In any era or place, nobles are seen as the highest power depending how long their family has been around for or how much wealth that family has either boosts their status. By forcibly moving nobles, Shi Huangdi showed haw powerful he was. Anyone can burn books or force commoners to work for the government, as has been shown in history. However, because nobles were practically the top power in the past, by forcing them to do something they did not want to basically shows who is truly in charge. Making the act of forcing nobles to move the most powerful.