Světový poštovní den / World Post Day 2013

This event is celebrated every year since 1969, on the anniversary of the founding of the UPU (Universal Postal Union), and commemorates all the hard work and social contributions of the postal services worldwide.
So across the world, post offices celebrate this special day in many different ways. This includes special philatelic exhibitions, free entrance in postal and communications museums, introducing new products and services, special cancellation marks, seminars, workshops and more! ... http://www.postcrossing.com/world-post-day