The mayor of Munich has tapped the first keg of beer to kick off the 179th traditional German folk festival Oktoberfest.

With only two blows of his hammer and a cry of "O'zapft is" — "It's Tapped" — Mayor Christian Ude inserted the first tap into the first keg as the festival opened Saturday, Sept 22.

More than six million guests from around the world are expected to descend on the beer tents of Munich to celebrate Oktoberfest through October 7.

Last year's visitors consumed almost 8 million 2-pint (1-liter) mugs of beer. This year a mug, called "Mass" in German, sells at up to €9.50 ($12.30).

German authorities keep security tight around the fairgrounds which accommodate hundreds of thousands of people at a time, although, they say, no concrete threat exists, The Associated Press reports.