10 year old Tilly Smith of the U.K., who was vacationing with her parents in Thailand at the time of last year's tsunami had studied tsunamis two weeks beforehand in her geography class. She recognized the signs of the coming tsunami and told her parents... who alerted hotel staff... who evacuated the area. Approximately 100 people were saved - this was the only beach in the area with no casualties.
You can read more about her story here
You can read about tsunami warning signs here