Only 3 days of advent to go! Number 21 is a pair of CYRK posters
posters are Polish circus/art posters created during the golden era of the Polish School of Posters (post World War II-1989). They "achieved a remarkable artistic quality as well as an unmatched degree of popularity"
These are 2 of my favourite ones, designed by Hubert Hilscher (1924 - 1999). There are some original ones for sale here