World Post Day is celebrated annually on 9 October to mark the establishment of the Universal Postal Union (UPU) in 1874 in Berne, capital city of Switzerland. In 1969, it was declared as World Post Day by the Universal Postal Union in Tokyo, Japan.
The motive behind celebrating the World Post Day is to create awareness of the role played by postal sector in people's everyday lives. The celebration encourages member countries to participate in activities aimed at spreading a broader awareness of their postal service's role among the citizens and how it helps them have a better life.More than 150 countries celebrate World Post Day every year in various ways. In certain countries, it is observed as a working holiday, while a number of countries use the event to introduce or promote new postal products and services. Some postal services also reward their employees for good service on this day.As the world celebrates World Post Day, here is a list of 10 of the rarest and most valuable stamps ever printed in the history of posts.