New Urbanism emerged in the late 20th century as a response to the negative impacts of modernist urban planning from the mid-1900s. The document provides a timeline of influential urban planning projects throughout history starting from ancient Greek and Roman cities to company towns in the 19th century industrial era and early 20th century garden cities. It then outlines the "perfect storm" of factors in the mid-1900s including racism, highway expansion, and modernist ideals that led to the decline of existing urban areas and rise of automobile-dependent suburbs, setting the stage for New Urbanism.