Perhaps as a child your association with knowledge of the Underground Railroad is that of disappointment over the realization that it was not, in fact, an underground railroad. For those not familiar with it, the Underground Railroad was a network of safe houses and roads for black slaves in the 19th century to use as a means of escape to the north and to Canada.
Harriet Tubman has gone down in American history as one of the most famous abolitionists, those out to abolish slavery. A former slave, Tubman was instrumental in the freeing of countless others. Often, she would go south instead of north to confuse authorities until they gave up, at which point she would turn back north.
Because smuggling infants was a troublesome affair, she often drugged them with paregoric, an opium derivative to keep them quiet. She also always had a revolver with her to discourage slaves from deserting her.
According to census data, Tubman and the others working in the Underground Railroad saved some 6,000 slaves, but the number could be as high as 32,000. Tubman's work was and is inspirational, and hopefully people like her will rise to help end the slavery epidemic in the modern world.