Finding errors in postage stamps is a joy. Here is a small collection of interesting errors in stamps. Errors can be of concept or print errors (wrong colors, inverted stamps)
USA - Inverted Jenny
The most famous error in postage stamp is this issue of U.S.Postage, 24 cents, known as "The Inverted Jenny" with an airplane printed upside down. This stamp (with error) is very rare was sold for more than US$ 1 million. It was issued in 1918.
France - 1937
Decartes stamp, comemorative of 300 years of his book "Discourse on the Method":
Wrong version: "Discours sur la méthode descartes"
Corrected in a later issue: "Discours de la Méthode" ?
Design by Henry Cheffer
The corrected Rene Descartes Stamp - Discours de la Méthode:
Where is the boatman ?
Corrected in a later issue:
Spain - 1950 - Sevilla - 1930 - Pro Union Iberoamericana.
Stamp with print error:
Monaco stamp, 1947 - Roosvelt collecting stamps with 6 fingers in his left hand.
He is examining a stamp with a magnifying glass (may be to also find some errors in his stamps?).
Exposition du Centenaire 1847-1947
Poste Aérienne (Air Post)
Facial value: 50 cents (50c)
Stamp engraved by Pierre Gandon (GANDON DEL. - Barlangue sc)
Detail from the six fingers in Roosvelt's hand:
The other "error" in this stamp is that he is not using philatelic tongs. It's not recommended to handle stamps directly with your own fingers.
Republique Francaise - RF - Du Tchad au Rhin issue stamp, 1946
Count the camels' legs... The camel with 3 legs error.
Stamp engraved by "Decaris", of the Paris Institute of Gravure.
This stamp was issued in many countries (French colonies): Cameroun, Guadeloupe, French Reunion, Madagascar, Indochina, New Caledonia, Côte des Somalies, Wallis et Futuna, Martinique and others.
Cameroun stamp with 3-leg camels
Martinique stamp with 3-leg camels