Tornado safety: What is the safest room in the house?

ScienceDaily (2010-07-14) -- For 18 horrific hours on April 3, 1974, a cataclysmic group of tornados spun through and sacked 13 states and one Canadian province, ravaging some 900 square miles and killing 148 people. An iconic photo snapped afterwards speaks a thousand words: amid devastation, one thing remained intact: an interior bathroom of a single house, whose walls had not been connected to the rest of the house.