In size and sophistication, the most impressive empire in the Americas was the Incas. Established in Peru in the twelfth century, the Incan empire united millio

Over its 2,700-year history, the Maya became one of the most complex and dominant indigenous civilizations in pre-Columbian America. They became masters in scie

Mostly known today for its complex pantheon and religious rituals, the Aztec empire was also highly advanced in the fields of science, technology, engineering,

At the dawn of Europe's Scientific Revolution, China was a major world power. With million-person cities, vast navies, and a robust trade in luxury goods, China