Please suggest me the most fascinating/enlightening biographies you've read.

No restriction as to "type" or profession of person. Just something you gained a lot of insight from. The Immortal Life of Henrietta Lacks and The Hiding Place have been two of my favorites. (Autobiographies count, too).

ETA: I cannot thank each of you enough for your suggestions! Your time is appreciated very much. I'm excited to begin...though I still need to choose where. I may number them and pull a number from a "hat."

Thank again!