The Universal Postal Union is one of the specialized organs of the United Nations (UN), which arose at the Berne Conference, Switzerland, on September 15, 1874, in which the creation of an organ with the character that will try to unify the postal services of the world, since previously the countries concluded bilateral agreements to fulfill the postal function, arriving at a time when it was necessary to consolidate an International Organization of which the States of the world would form part, in such a tenor on October 9, 1874 the General Postal Union was founded, which later changed its name to Universal Postal Union (UPU) in 1878. Because October 9 was the foundation of the Universal Postal Union (UPU) that day is celebrated worldwide as "World Postal Service Day". In 1948, the Universal Postal Union (UPU) became a specialized organ of the United Nations, after a treaty between the two institutions. The Universal Postal Union (UPU) is based in Bern, Switzerland.