12:00 AM marks the beginning of a new day in the 12-hour clock system. It is the moment when the clock strikes midnight, transitioning from one day to the next. This time is often associated with the end of the previous day and the start of a fresh 24-hour cycle. In many cultures, midnight is significant for various reasons, such as celebrations or rituals. For example, New Year's Eve festivities often culminate at 12:00 AM, symbolizing new beginnings. Additionally, in the context of timekeeping, 12:00 AM is the reference point for determining the hours that follow throughout the day.