When did postmodernism start and end?

Postmodernism is one of the most controversial movements in art and design history. Over two decades, from about 1970 to 1990, Postmodernism shattered established ideas about art and design, bringing a new self-awareness about style itself.

What year did postmodernism begin? What is postmodern pluralism? What characterizes postmodern architecture? What defines postmodern architecture? What is difference between art deco and art nouveau? What is an Art Deco home? What is Art Deco style house? What are the similarities and differences between modern art and contemporary art? What is the purpose of land art? What are different types of street art?