Stories of huge waves -- giant walls of water -- have long been written off as sailors' yarns. Now scientists have proof that these legends are true. Experiments in wave pools and with mathematical models have proven that freak waves can form, seemingly out of nowhere, as high as 35 meters. One single wave is enough to sink even the largest super-tanker. More than 200 ships have been wiped out by freak waves over the last twenty years. Scientists hope to shed light on their causes; their work may help to make collisions between freak waves and ships both predictable and avoidable.