Oktoberfest festival is held annually in Munich, Bavaria, Germany. And this year the mayor of Munich Christian Ude has tapped the first keg to kick off the 178th traditional German folk festival.

It is a 16–18 day festival held annually, running from late September to the first weekend in October. For this year, the opening ceremony of the world's biggest beer fest started in Munich on Saturday and runs until October 3.

Mayor Christian Ude inserted the first tap into the first keg as the festival opened its doors to the public Saturday. German authorities have increased the security around the fairgrounds this year, although they say no concrete threat exists, according to the Associated Press.

More than six million guests from around the world are expected to descend on the beer tents of Munich to celebrate Oktoberfest over the next 17 days, according to AP. Last year's visitors consumed some 7.1 million 2-pint (1-liter) mugs of beer. This year a mug, called Mass in German, tipped the 9-euro mark, selling at 9.20 euros ($12.66).

The Oktoberfest is an important part of Bavarian culture, having been held since 1810. Other cities across the world also hold Oktoberfest celebrations, modeled after the Munich event. The original Oktoberfest occurred in Munich, on October 12, 1810.

Only beer which is brewed within the city limits of Munich is allowed to be served in this festival. Upon passing this criteria, a beer is designated Oktoberfest Beer. Oktoberfest Beer is a registered Trademark by the Club of Munich Brewers.

Take a glimpse of the 178th traditional German folk festival Oktoberfest.

Oktoberfest Beer Fest
Munich Mayor Christian Ude taps the first barrel of beer during the opening ceremony for the 178th Oktoberfest in Munich September 17, 2011. Reuters
Oktoberfest Beer Fest
Munich Mayor Christian Ude hands over the first beer to Bavaria's Prime Minister Horst Seehofer (R) during the opening ceremony for the 178th Oktoberfest in Munich September 17, 2011. Reuters
Oktoberfest Beer Fest
A brass band in traditional Bavarian clothes takes part in the Parade of the Landlords and Breweries during the opening of the 178th Oktoberfest in Munich September 17, 2011. Reuters
Oktoberfest Beer Fest
A waitress carries the traditional 1-litre beer mugs at the opening of the Munich Oktoberfest September 17, 2011. Reuters
Oktoberfest Beer Fest
Revellers salute with traditional 1-litre beer mugs at the opening of the Munich Oktoberfest September 17, 2011. Reuters
Oktoberfest Beer Fest
Revellers toast with the traditional 1-litre beer mugs at the opening of the Munich Oktoberfest, September 17, 2011. Reuters
Oktoberfest Beer Fest
Green Party members Theresa Schopper, Claudia Roth and Margarthe Bause (L-R) toast during the opening ceremony for the 178th Oktoberfest in Munich September 17, 2011. Reuters
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