Felsengänge Nürnberg, Rock cellar network in Nuremberg, Germany.

Felsengänge Nürnberg is a tunnel and cellar system cut into the sandstone beneath Nuremberg's Old Town, begun in 1380 and used mainly for fermenting and storing beer. The passages reach several storeys deep and cover about 25,000 m². In the rock cellar, thick square pillars with rounded bases merge into a low, uneven ceiling; the floor is paved with large rectangular slabs, and small dark lamps on the pillars and walls light the tunnel, which runs off to the right into darkness.

From 1380 onward, Nuremberg's city council required every brewer to build cellars for fermenting and storing beer, which sparked the creation of this vast underground network. Over the centuries, brewers and workers expanded the passages to meet growing demand for the city's famous beer.

Nuremberg's 1303 council ordinance allowed only barley malt for brewing, reserving rye, wheat and spelt for bakers; this marks the start of the city's recorded beer history. Brewers dug cellars beneath their houses in the sandstone, and by the late Middle Ages up to 42 breweries supplied the town, which drank nearly five times today's amount of beer.

Expect narrow, low passages and be prepared for cool, damp conditions underground that are quite different from the street above. Sturdy shoes and a light jacket are helpful, since the temperature below stays constant year-round regardless of the season.

The tunnels were mostly kept secret until the mid-17th century. A ventilation system of shafts and ducts developed in the 14th century still keeps air moving through many sections today, and the cellars hold a constant 8 to 12 °C.