This timeline highlights noteworthy events and social, political, and economic trends in the history of the United States from 1492 to the 20th century. The documents shown were chosen from among those contributed to the World Digital Library by WDL partners. At the bottom of the timeline are listed the ten eras in the McRel Standards for United States History used in many schools: Three Worlds Meet (Beginnings to 1620), Colonization and Settlement (1585-1763), Revolution and the New Nation (1754-1820s), Expansion and Reform (1801-1861), Civil War and Reconstruction (1850-1877), The Development of the Industrial United States (1870-1900), The Emergence of Modern America (1890-1930), The Great Depression and World War II (1929-1945), Postwar United States (1945 to early 1970s), and Contemporary United States (1968 to the present). The documents on the timeline also can be viewed on an interactive map.