World Post Day is celebrated each year on 9 October, the anniversary of the establishment of the Universal Postal Union (UPU) in 1874 in the Swiss Capital, Bern. You can find out more on the UPU Website. The UPU in cooperation with UNESCO has, for over 45 years, organised an International Letter-writing Competition for young people aged up to 15. Entries must reach the UPU International Bureau no later than 5 May each year. Each year's theme is different, and the theme for 2018 is: "Imagine you are a letter travelling through time. What message do you wish to convey to your readers?" Find out more about the letter-writing competition.