Anther excellent presentation by Professor Niall Ferguson, "Empires on the Edge of Chaos". A timely release and very fitting as the American Empire is currently on the edge of chaos, just as Britain was in the early 20th century.
Here is the video link:
http://fora.tv/2010/07/28/Niall_Ferguson_Empires_on_the_Edge_of_Chaos#fullprogram