'''''The Underground Railroad''''', a network of people who helped [[fugitive]] [[slave|slaves]] escape to the North and to [[Canada]], was not run by any single organization or person. Rather, it consisted of many individuals -- many whites but predominently blacks -- who knew only of the local efforts to aid fugitives and not of the overall operation. Still, it effectively moved hundreds of slaves northward each year -- according to some estimates, the South lost 100,000 slaves between 1810 and 1850.