Why did the need for slaves drop during the 1800s

I would assume it has something to do with the 13th amendment since it abolished slavery

Fyi: 13th Amendment was passed in 1865

cultural achievements of the 1920's 2010  

1. cultural achievements and african american achievements in the 1920’s  

2. art and literature charles lindberg flew from ny to paris, france. became national hero; first transatlantic flight.  

3. greenwich village (new york) and the south side (chicago)  many artists, writers, and intellectuals flocked to these areas to share ideas  people lead bohemian, or artistic and unconventional, lifestyles

the congress realized that action had to be.