Harriet Tubman was an American abolitionist and political activist. Born into slavery, Tubman escaped and subsequently made some 13 missions to rescue approximately 70 enslaved people, including family and friends, using the network of antislavery activists and safe houses known as the Underground Railroad. During the American Civil War, she served as an armed scout and spy for the Union Army. In her later years, Tubman was an activist in the movement for women's suffrage. Born enslaved in Dorchester County, Maryland, Tubman was beaten and whipped by her various masters as a child. Early in life, she suffered a traumatic head wound when an irate overseer threw a heavy metal weight intending to hit another enslaved person, but hit her instead. The injury caused dizziness, pain, and spells of hypersomnia, which occurred throughout her life. After her injury, Tubman began experiencing strange visions and vivid dreams, which she ascribed to premonitions from God.