In a Gantt chart, how are milestones displayed?

A milestone represents a significant point or event in a project schedule and has no work effort or elapsed time associated with it. In a Gantt chart, this is depicted as an activity with zero-day duration, typically shown as a diamond symbol at the specific date, distinguishing it from task bars that span a time range.

An activity with one-day duration represents an actual work task, not a milestone; milestones have no duration by definition.

Activity-on-node with finish-to-finish precedence describes a dependency relationship in a network diagram (PDM), not how milestones are displayed in a Gantt chart.

An end-to-end bar graph showing time to complete a task describes how regular schedule activities are displayed in a Gantt chart, not milestones.