Final answer:
The Underground Railroad was a secret network that helped slaves escape to freedom. Harriet Tubman played a key role in leading many enslaved people to freedom.
Step-by-step explanation:
The Underground Railroad was a network of secret routes and safe houses used by nineteenth-century black slaves in the United States to escape to Northern free states and Canada with the aid of abolitionists and those sympathetic to their cause. The network was formed in the early nineteenth century and reached its height between 1850 and 1860. One estimate suggests that by 1850, 100,000 slaves had escaped via the Underground Railroad.
Harriet Tubman, a former slave herself, played a significant role in leading many enslaved people to freedom. She made her escape in the late 1840s and returned to the South more than a dozen times to rescue family and friends. Tubman and other participants in the Underground Railroad risked their lives to help slaves escape to freedom.