On this date in 1810, the first Oktoberfest was held in Munich, Bavaria, Germany.
Held annually, it is a 16-to-18 day folk festival, food, and traveling funfair that runs from mid or late September to the first weekend in October with visitors numbering more than six million from around the world. Other cities across the world also hold Oktoberfest celebrations modeled after the original Munich event.
It all began as a celebration when King Ludwig married Princess Therese of Saxe-Hildburghausen on October 12, 1810. The citizens of Munich were invited to attend the festivities held on the fields in front of the city gates to celebrate the royal event. Horse races were held on October 17th to honor the newlyweds. The precise origins of the festival and horse races remain a matter of controversy, but the decision to repeat the horse races, spectacle and celebrations in 1811 launched what is now an annual Oktoberfest tradition. (from me and Wikipedia)