This might be the oldest public restaurant in the world. It was erected in 1135 as a construction office for the building of the Regensburg stone bridge. In 1146 it was repurposed as a restaurant and served dockers, sailors, and workers in the St. Peter cathedral workshop. The current building replaced the original in the 17th century, but there is evidence that the "new" building has the same footprint as the 12th century structure. The family who currently owns the building took over in 1806. They serve 6000 sausages a day. Read more here.