One hundred and fifty National Geographic Society employees march in the Preparedness Parade on Flag Day, June 14, in 1916. With WWI underway in Europe and increasing tensions along the Mexican border, President Woodrow Wilson marched alongside 60,000 participants in the parade, just one event of many around the country intended to rededicate the American people to the ideals of the nation.

Not only the anniversary of the day the flag was adopted by Congress, Flag Day is also the anniversary of President Dwight Eisenhower's controversial addition of the words "under God" to the Pledge of Allegiance in 1954.

(Text adapted from "Culture: Allegiance to the Pledge?" June 2006, National Geographic magazine)