Why? - Harriet began her work on the railroad with other antislavery activists who helped save slaves from the south. But she actually saved her relatives first then saved others along the way.
Where? - She freed the slaves from the south & brought them to northern free states
"Black Moses" - The name was given to her because Moses from the Bible because he led people to freedom and that's what she seemed as to the slaves.
Obstacles? - There were some very difficult obstacles that she faced. Such as, she was wanted in the South for a reward of $40,000. Every-time she would go out to free slaves, it was like a risk of death for each and every one of the slaves and for her, but she still managed to finish the trip safely. Also, would think that the slaves would be willingly to do whatever they could to escape their slaveholders even if it means to walk for miles and miles. But you thought wrong, slaves doubted their freedom and they would give up because they would be either tired or too scared that they might be caught. But Harriet would always keep them back on track, she would say "you'll be free, or die a slave!". Tubman knew that if anybody were to turn, it would put her and the other slaves in danger of someone finding them, being captured, or even death. In the end, Harriet made 19 trips and saved over 300 slaves.
How does this relate to the theme? - This relates to the theme because since Harriet rescued the slaves, she made a big stand in American HIstory to risk her life.