Henry Laurence Gantt (1861-1919) was a mechanical engineer, and management consultant. He developed a visual scheduling tool in the second decade of the 20th century that we know today as a Gantt Chart.  Gantt Charts are used to show scheduled and actual project progress. Accepted as a commonplace project management tool today, it was an innovation of world-wide importance in the 1920s, based on his work studying ship building during WWI. Gantt charts were used on large construction projects like the Hoover Dam started in 1931 and the US interstate highway network started in 1956.