1900-1920: The infant mortality rate in the United States is 140 per 1,000 live births.

Today: Infant mortality has shrunk dramatically to below 8 per 1,000 live births.

1900-1920: The races in the American South are notoriously unequal. Segregation and discrimination are widespread, and most blacks live in poverty. During these two decades, there are 1,413 recorded lynchings of African American males, compared with 156 of whites.

Today: All races are equal under the law. There is increasing effort made to address economicinequities among African Americans and other non-whites in the South, and segregation is generally unacceptable.

1900-1920: Real estate and investment is becoming very popular among those who can afford it, given the rapid expansion of American cities.

Today: Buying property and real estate has once again become a popular way to get rich. Investment has taken on many new forms, and it is not so clear that the...