On Saturday, September 18th, with the tapping of the first keg by Munich Mayor Christian Ude and a cry of "O'zapft is!", Oktoberfest 2010 officially started in Munich, Germany. While this year marks the 177th Oktoberfest to be held, 2010 is the 200th anniversary of the very first Oktoberfest in 1810 (some years were missed due to war or cholera outbreaks). The Oktoberfest tradition started in 1810 to celebrate the October 12th marriage of Bavarian Crown Prince Ludwig to Princess Therese of Saxe-Hildburghausen. The citizens of Munich were invited to join in the festivities which were held over five days on the fields in front of the city gates. This year, festivities will run until October 4, 2010. Collected here are a few images from this opening weekend. Men in traditional Bavarian outfits participate in the traditional riflemen's parade of the Oktoberfest. A young woman wearing a traditional Bavarian "Dirndl" smiles as she receives a mug of beer in the Hofbrauhaus tent after the opening of the Oktoberfest beer festival at the Theresienwiese in Munich, southern Germany. Revelers reach out for a spilling mug of beer in the Hofbrauhaus tent after the opening of the Oktoberfest beer festival at the Theresienwiese in Munich.