A team of experts uses cutting-edge technology to examine the history of a Native American people who built a thriving metropolis in what is now Illinois, tracing the rise and fall of a civilisation that came into existence in 900AD, but vanished 400 years later. Much of the site is covered by forest, but archaeologist John Kelly obtains a view of what lies beneath and exposes the true scale of the city, while Bill Iseminger hunts down the engineering secrets behind the 10-storey pyramid that stood at its centre.
