A timeline diagram is very effective for showing events in chronological order. It consists of a horizontal bar representing time, which is marked with event items to indicate when the events happened or will happen (see example below).

It is important to identify the most appropriate segment of time to be illustrated from beginning to end. Long periods of no activity can be depicted by a gap or zigzag. However, too many gaps in the scale of the timeline will make it difficult for readers to understand.