* To understand the present. The past is a key to understanding the present. By learning about the events and people of the past, we can better understand the world we live in today. For example, by studying the history of the United States, we can learn how our country was founded, how our government works, and how our society has changed over time.
* To learn from the mistakes of the past. History can teach us valuable lessons about the mistakes of the past so that we can avoid making the same mistakes again. For example, we can learn from the history of World War II to understand how dangerous it can be to allow dictators to gain power.
* To preserve the memory of the past. History helps us to preserve the memory of the past for future generations. This is especially important for events like the Holocaust, which we must remember so that we can prevent them from happening again.
* To satisfy our curiosity. Many historians are simply curious about the past and want to learn more about it. This is a perfectly valid reason to study history, as it can help us to understand ourselves and our world better.
Of course, there are many other reasons why historians investigate the past. But these are a few of the most common.