Rahab (or Rachab)
Rahab was a prostitute who played a key role in the conquest of Jericho. Occupying a house upon the city wall, Rahab gave lodging to the two men sent into Jericho by Joshua on a reconnaissance mission. She hid them under stalks of flax on the roof, and told the king's soldiers that they had already left.
For helping the two men escape, Rahab was given the promise that she and her family would be spared when the Israelite army attacked Jericho.
When Joshua stormed into Jericho, Rahab had her entire family inside her house and a red chord hanging from the window, to signify to the Israelites not to harm anyone inside. Rahab and her family survived the destruction of Jericho, and lived among the Israelites.
There is some debate among commentators as to whether she is the same Rahab who is listed in Matthew 1:5 as being an ancestor of Jesus.