William H Whyte's book, The Social Life of Small Urban Spaces, was a landmark study published in 1980 of the way people adapted to the built environment and Movable Furniture of small plazas in larger cities.
William H Whyte's book cover
The documentary filming for the project was carried out by Whyte's research team in the late 1970s, using both rooftop and ground level camera teams. The resulting film (1979) is currently online at the Internet Archive, and thanks to the interplay between its many fans and its owners it cycles rapidly through YouTube upload and takedown. video 
As a sociologist, Whyte's conclusion was that urban planners should pay more attention to what people actually do in places—especially those they use frequently—before fixing on their ultimate design. In the book and the film he noted many instances of aesthetic design principles resulting in social failure.
He also noted creative reuse of given urban architecture, adaptive moving of flexible parts (plaza chairs) based on social need, and the interplay of people, light and shade during the day.