... that the first Penny Post was established in London in 1680 by William Dockwra nearly 200 years before the better known Uniform Penny Post that was part of the postal reforms of 1839 and 1840 in Great Britain.
... that Czesław Słania (1921-2005) is the most prolific stamp engraver, with more than 1,000 post stamps for 28 postal administrations?
... that a forerunner is a postage stamp used during the time period before a region or territory issues stamps of its own?
... that the Royal Philatelic Society is the oldest philatelic society in the world, founded in London in 1869?
... that Marcophily is the specialised study and collection of postmarks, cancellations and postal markings applied by hand or machine on mail?
... that throughout U.S. history, different types of mail bags have been called mail pouch, mail sack, mail satchel, catcher pouch, mochila saddle mailbag, and portmanteau depending on form, function, place and time?
... that Non-denominated postage are postage stamps that do not show a monetary value on the face?
... that the Daguin machine was a cancelling machine first used in post offices in Paris in 1884?
... that the first airmail of the United States was a personal letter from George Washington carried on an aerial balloon flight from Philadelphia by Jean Pierre Blanchard?
The Benjamin Franklin Z Grill, or simply "Z-Grill", is a 1-cent postage stamp issued by the United States Postal Service in February 1868 depicting Benjamin Franklin. The Z-Grill is distinguished by having the so-called "Z" variety of a grill pressed into the stamp, creating tiny indentations in the paper whose purpose was to allow the cancelling ink to be absorbed better by the stamp's paper. The use of grills was found to be impractical and they were soon discontinued.
The 1-cent Z-Grill is generally considered the rarest and most valuable of all US postage stamps. There are currently only two known 1-cent 1868 Z-Grills, both with cancellation marks.