The mysteries of the sea offer the allure of adventure for scientists of all ages, and advances in technology supply the tools to explore this frontier. Therefore, the Discovery Channel, Woods Hole Oceanographic Institute (WHOI), and John Hancock Financial Services sponsored the Extreme Deep: Mission to the Abyss—an interactive exhibit that toured science museums nationwide during January 2001–September 2004. This article describes Extreme Deep and includes a list of Internet resources.