A 63-year-old generally healthy woman with a history of migraine was vacationing in Tuscany with her husband in July 2013. She dived into a cold swimming pool for her customary early morning swim. After swimming three laps, she experienced the worst headache of her life, “which came on like a rocket.” She did not lose consciousness, but felt some confusion. She decided to sleep, and awakened after a few hours with continued headache and confusion, in addition to nausea and vomiting. After contacting her general practitioner in their home of New York City, her husband transported the woman to an emergency room in Siena, Italy.