Every fall, Theresienwiese, a square in Munich, Germany, transforms into one of the world"s largest festivals—Oktoberfest. First held in 1810 to celebrate a royal wedding, it has grown into a 16- to 18-day tradition attracting more than 6 million people from around the globe. The scale is staggering: The festival grounds span about 4.5 million square feet and host 14 main tents, each seating thousands. Each year, visitors consume around 7 million liters of beer, along with mountains of pretzels, sausages, and gingerbread hearts. All beer served at Oktoberfest comes from Munich breweries and meets the strict standards of the Reinheitsgebot, the German Beer Purity Law.