Gantt charts were first created in the mid-1890s and revised by Henry Gantt in the early 1900s. Gantt charts are often used in businesses to plan projects and events. They allow managers to stay focused on both monetary and time constraints. Simple Gantt charts list project activities against points in time. More elaborate Gantt charts show more details, such as milestones (discussed below). Time slots/duration would include, for example, the project start date, intermediate time points of importance, and the ending date.