Read it, define it, then find it

Harriet Tubman escaped slavery in 1849, walking north by night and hiding by day. She could have stayed safe in Philadelphia. Instead she turned around and went back, again and again.

She learned the land the way a sailor learns the sea. Moss grows thicker on the north side of a tree. The Big Dipper points to the North Star. A song sung at the right moment could warn a family that tonight was the night.

Over roughly a dozen missions she guided about seventy people to freedom, and she often said that she never lost a passenger. During the Civil War she served as a scout and a nurse, and she led an armed raid that freed more than seven hundred people along the Combahee River.