On August 31st, 2007, then 27-year-old Marissa Kristal was running on a treadmill when the most excruciating pain she ever felt struck her in back of her head and immediately washed over her entire skull. She was certain she was having an aneurysm. Mercifully, she was wrong. Marissa suffered a subarachnoid hemorrhage (SAH). This means a vein in her brain burst. When a person suffers a SAH the cerebrospinal fluid in the subarachnoid space becomes bloody - a very dangerous and often life-threatening occurrence. Sufferers tend to experience "the worst headache of their lives." The pain is sudden and acute, and usually makes people feel dizzy, see double, become nauseous, get a stiff neck, feel a 'popping' sensation in their head, and even begin to lose their mental abilities. Marissa experienced all these symptoms. A healthy and active young woman, before this terrifying incident Marissa had a sparkling health record. Now, she is the girl who stared death in the face and prevailed. Marissa could have easily died that day, or lost any number of her cognitive abilities, but she didn't. This is Marissa's tale of survival, and the tremendous growth, self-discovery and assuredness that comes from fighting for your life. Anyone that has ever faced hardship and ultimately triumphed will be inspired by What Doesn't Kill You.