Despite what we want to believe, there are more slaves alive today than at any time in the history of mankind. We have more slaves because we have more people. Slaves make up a smaller fraction of our population than ever. We are not necessarily morally superior to the people who died generations ago. Fossil fuels cost less to use than human labour. Oil, natural gas, and coal have largely replaced slave labour–at least for now. If you want to get involved in the fight against the abhorrent practice, here is a list of ways to join the cause.