The Progressive Era (8 h 10 m, 30 agos 1890 año – 15 h 39 m, 22 jul 1920 año)
Descripción:
 social activism and political reform across the United States that fought for the eliminating problems caused by industrialization, urbanization, immigration, and political corruption. ( Suffrage, Muckrakers, Populist) 
Añadido al timeline:
fecha:
8 h 10 m, 30 agos 1890 año
15 h 39 m, 22 jul 1920 año
 ~ 29 years