U Fleků has been a brewery and pub since 1499 — one of the oldest continuously operating breweries in the world, and certainly one of the oldest in Prague. The pub serves a single product: its own dark lager, Flekovský Tmavý Ležák, brewed on the premises in a 13-hectolitre kettle that has barely changed in a century.
The complex is large, with several garden and indoor seating areas decorated with painted murals and medieval touches. It is undeniably touristy, but it is touristy in the way a 500-year-old institution earns the right to be. The dark beer is excellent — malty, smooth, not overly sweet. Go for the history and the beer; the food is secondary.