Few of the visitors to the Bistro Nobel are aware of what is right below them. The chairs in the restaurant of Stockholm’s Nobel Prize Museum hide the signatures of Nobel laureates on their undersides, not visible unless you turn them over or crawl beneath them.

The tradition of having Nobel laureates sign the underside of the chairs started during the event’s 100-year anniversary in 2001, but there are signatures going back further than that. Often, laureates visit the museum during their trip to Stockholm for the Nobel prize ceremony and have lunch in the restaurant. After their meal, they are encouraged to sign the chairs they have been sitting on.

So after a visit to the museum, humbled and blown away by the genius of all the people honored with a Nobel prize, you can head over to the restaurant for their classic Nobel ice cream. But the real joy of visiting the restaurant is flipping chairs upside down.