On 4th June 1968 the Poster Museum at Wilanów was opened as the world's first poster museum, a branch of the National Museum in Warsaw. Similarly to other museum-type institutions, the Poster Museum collects, describes and preserves works of art.  Presently the Museum boasts one of the largest collections of art posters in the world, consisting of over 55,000 items. In putting the collections together, top priority is given to the artistic, rather than documentary aspects, although the latter are also given due consideration in the development of sub-collections illustrating major historical periods.