Margen
In December 1934, the printing presses of the US Treasury began stamping the largest bill in the country's history: one hundred thousand dollars, bearing the portrait of Woodrow Wilson and the golden seal of the gold certificates.
No private citizen ever touched one. It was never designed for shops or neighbourhood banks: its sole purpose was moving money between the Federal Reserve and the Treasury, in an age when electronic transfers did not exist and large official payments travelled on paper. Around 42,000 were printed in just a few weeks.
When electronics retired paper, almost all of them were withdrawn and destroyed. The few that survive remain government property: the law forbids private individuals from owning one, no matter how much they offer. They can only be seen behind glass, as at the Smithsonian.
The largest bill that truly circulated was the $10,000 note, withdrawn in 1969; ever since, the ceiling on the street has been the hundred. The hundred-thousand still exists, technically valid and locked away forever: real money that can never be spent.