Beer and merriment flow at the 189th Oktoberfest in Munich

Tens of thousands of revelers marked the opening day of the 189th Oktoberfest. The celebration began Saturday and runs through Oct. 6 in 18 large tents covering the fairground. It is considered the world’s largest folk festival. Security this year includes stepped-up safety measures in the wake of a deadly knife attack in Solingen which is roughly 470 kilometers or 300 miles northwest of Munich. About 6 million visitors are expected over the festival’s 16 days and they can expect to shell out between 13.60 and 15.30 euros for a liter mug of beer. That's 33 fluid ounces.