1st Dec is, well, great union day.
On 1918 all of the territories that make up romania today (Muntenia, Moldova, Transylvania, Dobrogea) united. Some romanians celebrate this day by either dressing up in national clothes (Ie) or hanging up the country's flag or both! Yayy!!!
Several countries have in the past banned ruling queens, but lacked any requirement that the king be male. This led to King Anna of Poland, and King Mary of Hungary.