This site may well be unique. It was designed by Chris Milligan, a professor of Education at McGill University for later childhood elementary students.
He describes the site as a "series of activities where students "dig" for sunken treasure on the pages of National Geographic Magazine (NGM). The reader uses NGM maps, diagrams, photographs and captions to locate specific issues of the NGM that detail the wreck of two famous gold-laden Spanish Galleons that sank in a hurricane in the 17th century."