The self-proclaimed First Emperor of China, Qin Shi Huang is one of the most important figures in Chinese history. Under his leadership, massive reforms to the legal and economic systems took place – and, not incidentally, numerous scholars and writers were outlawed or executed, and their books burned. He also decreed vast infrastructure projects, including a massive program of road-building, and the creation of the Great Wall of China.
Huang was not responsible for the entire wall, but rather, for the construction of links between pre-existing sections and extending the ends of the them. The project was a long one, and would be completed for centuries, but it sure kept thousands of peasants to busy to rebel for generations at a time, and may have even served some defensive purpose (which is usually considered to be the reason for its construction).