In the 19th and early 20th centuries, scientists were so fascinated by race that thousands of indigenous people from all over the world were put on display in human zoos. They were not intended as merely entertaining freakshows but also scientific demonstrations of racial difference. Across the western world millions gawped in fascination at these "uncivilised savages" and would depart convinced of the superiority of the white race. Human Zoo: Science’s Dirty Secret explores the phenomenon of human zoos and tells the poignant story of Ota Benga, a Batwa pygmy from the Belgian Congo, who was first put on display at the 1904 St Louis World's Fair and then the Bronx Zoo where he was labelled as the 'missing link'.