The document discusses the Underground Railroad, which was a secret network that helped fugitive slaves escape from the southern United States to Canada between 1800-1865. It operated through various methods of transportation and routes, including water routes, walking trails, and railways, to help slaves evade capture by slave owners and reach the safety of Canada, where slavery had been abolished. Those who assisted the escaping slaves faced risks, as the Fugitive Slave Law required all Americans to return escaped slaves to their owners.