The 1913 Liberty Nickel is one that has been surrounded in mystery since it's discovery. There has only been 5 known to exist, 2 of them are in a museum and the other 3 are in a private collection. It is believed that five specimens were struck at the U.S. Mint in Philadelphia sometime between the Summer of 1912 and early February of 1913. One theory says that the coins were struck as advance test pieces around July of 1912, with the expectation that the series would continue the following year anyway. Another theory proposes that someone was burning the midnight oil at the Mint, and struck the five specimens before the dies were destroyed in preparation for the change to the Buffalo Nickel, which began production in late February of 1913. I do believe its possible that someone could find another one in a old bag of money or old collection. I also wonder how do they know these coins are real? It's possible that someone had made a 1913 die to counterfeit the coin in there garage. But then later found out that they had changed to the buffalo nickel and destroyed the die and the coins that they had not spent. But this is a really far fetched theory!