History has been formed over enormous time of destructions and re-creations, being affected each time by coincidence. Each moment is a turning point for history to go toward any directions. Therefore, history could lead its course into various ways, and it is defined by an action taken at the point. It is the action that opens history. A sudden, radical change of history is often caused by a free, creative action by an individual, such as revolution, invention or discovery. Here is a thought on “What is history?”, focusing on such actions that move human history.