Billions of dollars circulate daily, but some $100 bills are worth far more than face value. Numismatics experts suggest closely checking your cash for rare variations like gold certificates, which could fetch up to $2 million.

Gold certificates, first issued in 1863 during the Civil War, were used to represent large gold reserves. Today, any pre-1880 certificate is highly valuable. Only three $100 gold certificates remain, two of which are housed in the Smithsonian. The third was sold for over $2 million in 2013, making it the most expensive U.S. banknote in history. Keep an eye out—you could be holding one of these rare treasur

es!