Keywords: Liberty bell 13c 1961 issue.jpg en Liberty bell stamp of 1961 1961 U S Post Office; Smithsonian National Postal Museum U S Bureau of Engraving and Printing; Imaging by Gwillhickers PD-USGov Uploaded with UploadWizard Liberty Bell on stamps Stamps of the United States 1961-1970 Commemorative stamps of the United States Airmail stamps of the United States |