In 1924, Harold Bucklin of Brown University spent a year as a Visiting Professor in Shanghai. The family has established a website dedicated to the photographs Bucklin took.
http://www.bucklinchinaarchive.com/index.php
I stumbled on this website four or five years ago and it has grown and keeps growing. This is a wonderful visual record of China in a period of great political chaos. On one level is the struggle for power over a nation and on another, life's daily struggle of the ordinary people. Even in the clothing of the ordinary people, we see two worlds, that which evolved over centuries and that of encroaching westernisation.
In the Bucklin site, there is also a link to "Virtual Shanghai", another interesting site covering this period of upheaval.