Remote memory is the ability to remember things and events from many years earlier. This is a function of long-term memory which the brain stores differently than recent or short-term memories. Short-term memories are stored in different areas of the brain than long-term memories.
Additionally, when a person is young there is a great deal of emotion attached to event memory. The intensity of the emotion involved causes these memory traces to be very intense. This is why, as a person grows older, that they can remember things from childhood and young adulthood yet have difficulty remembering things that have happened recently.
For instance, even when a person is in their 20's or 30's they can look back to their teens and wonder why they can remember every word of a favorite song but have difficulty remembering details about work or recreation.