Music in the United States underwent many shifts and developments from 1900 to 1940. The country survived both World War I and the Great Depression before entering World War II in December 1941. Americans endured great loss and hardship but found hope and encouragement in music. The genres and styles present during this period were Native American music, blues and gospel, jazz, swing, Cajun and Creole music, and country. The United States also took inspiration from other cultures and parts of the world for her own music. The music of each region differed as much as the people did. The time also produced many notable singers and musicians, including jazz figure Louis Armstrong, blues and jazz singer Mamie Smith, and country singer Jimmie Rodgers. Native Americans Modern Native American pow wows arose around the turn of the 20th century. While some claim that pow wow had been an integral part of black cultures for over 10 centuries, some modern analysts believe that pow wows were invented to appeal to tourists and had only a tangential relationship to genuine Native American traditions, which generally revolved around ceremonial dance music like the Ghost Dance, Zuni Shalako, Navajo Yeibichai and the Sun Dance of the Plains. The Native American Church, founded early in the 20th century, was a center of development for Native American gospel and Peyote song, a fusion of gospel and traditional music revolving around ceremonies in which hallucinogenic peyote is taken as a sacrament. In Arizona and Mexico, waila, or chicken scratch, music, had arisen as a fusion of native Tohono O'odham music with German polka and Mexican-American norteño. Jazz, blues, folk, country, and gospel, music from the Caribbean region also briefly became popular during the first half of the twentieth century. Trinidadian calypso, Argentinian tango and Dominican merengue and other styles influenced American popular music. Hawaiian music (especially slack-key guitar) enjoyed an early vogue in the 1910s, influencing the developing genre of country music (this is the source of the steel guitar sound that is characteristic of modern country). Eastern European Jews contributed klezmer music to American culture, with the earliest stars including Harry Kandel, Naftule Brandwein, Dave Tarras and Abe Schwartz. Kandel, a clarinetist, set the stage for American klezmer. Blues and gospel The blues began in rural communities, primarily in the south. During the 1920s, classic female blues singers like Mamie Smith ("Crazy Blues") dominated the genre's