http://www.dig4coins.com/news/latest-news/the-1933-saint-gaudens-gold-double-eagle-coin.html

One of the most valuable, if not the most valuable, coin is considered to be the 1933 Saint-Gaudens Gold Double Eagle1933 Saint-Gaudens Gold Double Eagle. It actually was never officially issued. Still it appeared from 1907 until 1932. Although in 1933 there were 445,500 Double Eagle minted, none were released into circulation because of the changes made in currency laws during the Great Depression.