SCHAUMBURG, Ill. -- Rare coin collectors from around the world are meeting in Illinois for a very special auction.

An extremely rare 1913 liberty head nickel, known as the lost nickel, is the star of the show.

The four day auction runs through Saturday and over 10,000 items will be there with a total value at over $40 million.

The lost nickel is just one of five coins minted 100 years ago in Philadelphia.

"What makes this special is it has the old style design on the coin. In 1913 we switched over to the now famous buffalo design," said Todd Imhof, VP Heritage Auctions.

No one really knows why only five of the coins were minted but that nickel is now worth 60-million times more.