1920-1929 (African-American)
1921
Immigration Act of 1921

Immigration Act of 1921 limits the number of immigrants allowed to enter the United States in a year.

1923
Garret Morgan

African American, inventor Garret Morgan patented the traffic signal.

1928
Marjorie Joyner

Marjorie Joyner patents the permanent hair-waving machine.

1929
Ernest Just, Ph.D.

Ernest Just, Ph.D., publishes his theory of the fundamental role of the cell structure in the development of organisms in the fields of marine biology and zoology.

1920-1940
Harlem Renaissance

The Harlem Renaissance marks a cultural explosion for African Americans in the arts and entertainment.