The Progressive Era (8h 10min, aug 30, 1890 y – 15h 39min, jul 22, 1920 y)
Description:
 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) 
Added to timeline:
Date:
8h 10min, aug 30, 1890 y
15h 39min, jul 22, 1920 y
 ~ 29 years