 Czech and German traditions combined to sponsor the polka.The Southern Diaspora of the 20th century saw more than twenty million Southerners move throughout the country, many of whom moved into major Midwestern industrial cities such as Chicago, Detroit, Cleveland, and St. Louis.Along with them, they brought jazz to the Midwest, as well as blues, bluegrass, and rock and roll, with major contributions to jazz, funk, and R&B, and even new subgenres such as the Motown Sound and techno from Detroit or house music from Chicago.