The 20th century was an era of unprecedented transformation, defined by a "radical transformation of social attitudes," global decolonization, and the emergence of modernism. Often described through Eric Hobsbawm's lens as the " Age of Extremes ," it balanced massive technological leaps with devastating global conflicts.

: Modernism emerged in the early 20th century, breaking away from traditional artistic styles through radical techniques like abstraction and collage . This shift reflected the social and technological upheavals of the time.

To explore this era effectively, historians recommend focusing on the " five C's of historical thinking ": change over time, causality, context, complexity, and contingency. American Community Survey Information Guide - Census Bureau