Open every day (except December 25)
10:00 am to 5:30 pm
Admission is always free!
2 Massachusetts Ave., N.E.
Washington, DC 20002
24c Curtiss Jenny inverted block of four, 1918.
Loan from William H. Gross.
This upside-down blue plane within a red frame is the most famous U.S. stamp and one of the world’s most famous printing errors. Only one misprinted sheet of 100 stamps was sold.