1924: The first airplanes to circle the globe arrive in California after flying 30,000 miles in five months.

1996: The National Aeronautics and Space Administration (NASA) announces that Mars may have supported life-forms. The report cites evidence gained from an analysis of a meteorite found in Antarctica in 1984.

1924: The United States Congress passes the Johnson-Reed Act, which removes restrictions on immigration from Canada and Latin America. As a result, by the end of the year, immigration numbers from these areas break previous records.

1996: Mexico and the United States sign several pacts including the Migrants' Rights pact, which grants rights to legal and illegal Mexicans in the United States.

1924: The United States Congress recognizes Native Americans as U.S. citizens.

1996: The South African government makes its final transition from apartheid to democracy with the adoption of a new constitution. President F. W. de Klerk resigns.