"W" is for World War II (1941-1945). Prior to the entry of the US into World War II, the federal government constructed or expanded military installations, including Camp Jackson (Columbia), Camp Croft (Spartanburg), the Navy Yard (Charleston), and several smaller bases. At least 900,000 men received military training in South Carolina. More than 180,000 Carolinians (including 2,500 women) served in the armed forces. Thousands more wanted to serve, but 41% of those examined were rejected for mental or physical problems.