1890, which required "equal, but separate" railroad accommodations for white and non-white passengers. This court decision upheld Jim Crow laws that had started to form in the 1870s. In 1898, white Democrats in the Louisiana state legislature passed a new disfranchising constitution, whose effects were immediate and long-lasting. The disfranchisement of African Americans in the state did not end until national legislation passed during the Civil Rights movement in the 1960s. In the early-to-mid 20th century, many African Americans would leave the state in the Great Migration. They moved to mainly urban areas in the North and Midwest. The Great Depression of the 1930s would hit the states economy hard, as mostly agricultural state at the time, farm prices had dropped to all-time lows. In the states urban areas such as New Orleans, many warehouses and businesses had closed, leaving many unemployed. The Federal Emergency Relief Administration would help flow money into the state, providing employment opportunities for Louisiana projects. World War II would help accelerate the industrialization of Louisiana's economy and provide further economic growth. In the 1950s and 1960s, the Civil Rights movement had started to gain national attention, and with the passing of the Civil Rights Act of 1964 and Voting Rights Act of 1965, disfranchisement of African Americans in the state had ended. In the late 20th Century, Louisiana saw rapid industrialization and rise of economic markets such as oil refineries, petrochemical plants, foundries, along with industries of produce foods, fishing, transportation equipment, and electronic equipment. Tourism also became important to the Louisiana economy, with Mardi Gras becoming a known major celebration held annually since 1838. In 2005, Hurricane Katrina struck Louisiana and surrounding areas in the Gulf of Mexico, resulting in major damages. A $15 billion dollar new levee system built in New Orleans would take place from 2006 to 2011. Prehistory Lithic stage The Dalton tradition is a Late Paleo-Indian and Early Archaic projectile point tradition, appearing in much of Southeast North America around 8500–7900 BC. Archaic period During the Archaic period, Louisiana was home to the earliest mound complex in North America and one of the earliest dated complex constructions in the Americas. The Watson Brake site is an arrangement of human-made mounds located in the floodplain of the Ouachita River near Monroe in northern Louisiana. It has been dated to about 3400 BC. The site appears to have been abandoned about 2800.