Harriet Tubman's Unsung Heroism
Harriet Tubman is famous for her role as a "conductor" on the Underground Railroad.
While her work as a scout and spy for the Union Army during the Civil War is not as well
known, it is no less heroic. One of her most important military successes occurred when
Union forces were preparing to raid a Confederate-held area along the Combahee River
and destroy the South's supply routes. The Confederate Army had hidden mines
throughout the waters, endangering the Union soldiers, but Tubman found a way to
bypass this hazard. Knowing that the mines had been placed by enslaved people forced to
work for the Confederates, she led a secret mission into enemy territory and convinced
the enslaved workers to divulge the mines' locations. Armed with this information,
Tubman was then able to guide Union gunboats safely past the mines during the raid. The
Union soldiers not only successfully raided the Confederate supplies but also freed more
than 700 enslaved people along the way.
What is the main idea of the passage?

Harriet Tubman did heroic work as a conductor for the Underground Railroad
and as a Union scout and spy.

Working as a Union scout and spy, Harriet Tubman secretly met with enslaved
workers in Confederate territory.

Working as a Union scout and spy, Harriet Tubman played an important role
in a Union Army raid.