The Star of Bethlehem was the second largest diamond in the world, found on a Christmas morning in the 1880's. It may have been found in Israel, or in Egypt, but presumably takes its name from the date of its finding.
Usually displayed in a museum in Cairo, Egypt, the diamond was loaned to the McMillan Museum in San Francisco, during the 2007 Christmas season. It was due to be returned shortly before Christmas, but a crew of thieves, led by retired parole officer Michael Kenworthy, plotted to steal it.
Their plan was thwarted by Adrian Monk. Because of the diamond's symbolic value to the Christmas season, Monk was lionized as an American hero and "The Man Who Saved Christmas" by reporter Brandy Barber. It costs over $30,000,000.