In northern Switzerland, the city of Zurich operates as a global financial center. But its Old Town (also known as the Altstadt), showcases the quieter, historic side of the city. Nestled the heart of the Altstadt, in a building originally constructed as a residence for nobles more than 650 years ago, sits Oepfelchammer. The tavern is known for its long history and, more recently, its unique drinking ritual.

The building earned its name after its stint as a convent’s apple storage unit. In the 17th century, the property became a bakery, and it was a baker who first got permission to start serving drinks in 1801. Today, the restaurant serves Swiss fare and fine wine. After 6:00 p.m., visitors to the tavern are only permitted to drink water, grape juice, or wine. But most importantly, and much more idiosyncratically, Oepfelchammer hosts a drinking ritual known as balkenprobe, or beam challenge.

To attempt the challenge, participants scramble and kick their way up onto a ceiling beam. Then, they crawl over to the adjacent rafter and hang upside-down. A waiter brings over a glass of white wine and the inverted guest then attempts to down the entire glass without spilling it. (You can watch someone successfully complete the mission on YouTube.)

Should they succeed, the winner adds their name to the collection of carvings on the wall. Anyone who initially fails is entitled to two more attempts. Regardless of the outcome, all who brave Oepfelchammer’s balkenprobe are entitled to a wholly unique kind of hangover.