All kinds of cash is on display at the Stephens Convention Center where collectors are buying, selling and trading rare coins and currency.
"The World's Fair of Money now through Saturday at the Rosemont Convention Center is a once in a lifetime opportunity for people to come in and see some of the most valuable, historic and rare coins and paper money in the world," Donn Pearlman, World's Fair of Money, said.
The American Numismatic Association is sponsoring the show, which isn't just about money -- it's also about how values change. For instance the Smithsonian has gold coins from the 1849 gold rush. Gold coins, that have gone up just a bit since the 49'ers.
"They were worth $20 in trade," Dr. Richard Doty, Smithsonian Institution, said. Now they're worth, "Ahh, in the hundreds of thousands of dollars or in the case of 1849, perhaps $20 million."
The Department of the Treasury and the Bureau of Engraving and Printing give quite the history lesson. It's all about how from the 1860's to 1929 all U.S. currency was printed with a method called intaglio. Just four bills at a time-- printed by an army of workers.
"Originally we had over 600 of these presses right here and twelve hundred people in the press room alone," Mike Beck, Dept. of Engraving, said.
Also at the show- twelve $100,000 bills with President Woodrow Wilson said.
"The $100,000 bill at the time was an easy mechanism to transfer funds between federal reserve banks," Kevin Brown, Department of the Treasury, said. "No it was never in any public hands."
The treasury department all brought along their billion dollar display case, which includes two notes worth $500 million and million dollar coupons -- just for extra spending.