South Dakota experiences a temperate continental climate, with four distinct seasons and precipitation ranging from moderate in the east to semi-arid in the west. The ecology of the state features species typical of a North American grassland biome. Humans have inhabited the area for several millennia, with the Sioux becoming dominant by the early 19th century. In the late 19th century, European-American settlement intensified after a gold rush in the Black Hills and the construction of railroads from the east. Encroaching miners and settlers caused conflict that triggered a number of Indian wars, ending with the Wounded Knee Massacre in 1890. Key events in the 20th century included the Dust Bowl and Great Depression, increased federal spending during the 1940s and 50s for agriculture and defense, and an industrialization of agriculture which has much reduced family farming. While several Democratic senators have represented South Dakota for multiple terms at the federal level, the state government is largely dominated by the Republican Party, whose nominees have carried South Dakota in each of the most recent 12 presidential elections. Historically dominated by an agricultural economy and a rural lifestyle, South Dakota has recently sought to diversify its economy in areas, including biomedical research and alternative energy fuels, to attract and retain residents. South Dakota's history and rural character still strongly influence the culture of the state. dai ly ve may bay vé máy bay tết ve may bay gia re vé máy bay khuyến mãi đặt vé máy bay giá rẻ dat ve may bay gia re