The Egyptian pyramids and the Great Wall of China are proof that projects of tremendous scope, employing tens of thousands of people, were completed in ancient times. It took more than 100,000 workers some 20 years to construct a single pyramid. Who told each worker what to do? Who ensured that there would be enough stones at the site to keep workers busy? The answer is managers. Someone had to plan what was to be done, organize people and materials to do it, make sure those workers got the work done, and impose some controls to ensure that everything was done as planned.