There were so many things that happened in the 1920s that I will have to be selective. Let me name three important events.
First, in 1929 October 29th, the stock market crashed. It was called black Tuesday. This was the beginning of the great depression. This point is very applicable to us today in view of our economy.
Second, from an entertainment and technology point of view, John Baird creates the first television and in 1928 he creates a color television. As you can imagine, this will be an important development for society.
Third, Charles Lindbergh is the first person to fly across the Atlantic Ocean. He went from New York to Paris. This took place in 1927. At creates a big push forward in aviation.
One of the most widely publicized events of the 1920s was the Loeb and Leopold murder and the subsequent trial in which they were defended by Clarence Darrow. Leopold later wrote a book about the whole subject. I believe the title is99 Years to Life. I also believe a movie was made about the case starring Orson Welles as Darrow, but I can't think of the title.
Another widely publicized event was the so-called Scopes Monkey Trial in which a high school teacher was on trial for teaching Darwin's theory of evolution. Clarence Darrow acted as an attorney for the defense and the famous William Jennings Bryan participated in the prosecution. What made the case so notorious was that it aired the arguments for evolution versus creationism.
Clarence Darrow described these trials in his autobiography.
A great movie titled Inherit the Windwas made about the Scopes trial. It stars two famous actors, Spencer Tracy and Frederic March, and is readily available on DVD.
Babe Ruth hits 60 homeruns.
Boston Red Sox sell Babe Ruth
Yankees have firt team uniform numbers.
Johnny Weismuller swims 100 meters in 58.6 seconds.
Geratarude Ederle swims English Channel
Jim Thorp retired from professional football
United States Army biplanes fly around the World
Lindbergh flies New York to Paris
Jack Dempsey Heavy Weight chanion
Georgia O'Keeffe paints Blue and Green Music
Miles Davis born
Samuel Insull was to the 1920's like Tom Watson to the 1960's or Bill Gates to the 1990's
1920's let see um.... the great depression , they began drinking wine , many movies were made and started wearing "flapers"