South Dakota's culture reflects the state's American Indian, rural, Western, and European roots. A number of annual events celebrating the state's ethnic and historical heritage take place around the state, such as Days of '76 in Deadwood, Czech Days in Tabor, and the annual St. Patrick's Day and Cinco de Mayo festivities in Sioux Falls. The various tribes hold many annual pow wows at their reservations throughout the state, to which non-Native Americans are sometimes invited. Custer State Park holds an annual Buffalo Roundup, in which volunteers on horseback gather the park's herd of around 1,500 bison.