Kraków's Main Market Square and its cellars

Most visitors cross the Main Market Square once, photograph the Cloth Hall and move on. This route stays longer, and it keeps going down. Below the square lies a museum built over excavated medieval stalls, and in a palace cellar off it a cabaret has met since 1956. Above it stands a single tower, the last piece of a town hall that was pulled down.

You start at the university's oldest courtyard just off the square, circle through the middle of it, and finish at the oldest church on its edge.

Begin a few steps from the square, at the Collegium Maius, the Jagiellonian University's old college building. Until 1940 the university library was kept here. Today it is the university's museum, with lecture rooms, a common hall, professors' rooms and a treasury of rectors' maces and an early globe. The Gothic courtyard is the reason to stop, even if you skip the rooms.

The Piwnica Pod Baranami takes its name from the Palace Under the Rams, the 19th-century seat of the Potocki family, and it lives in the palace cellars. It began in 1956 as a student art club led by Piotr Skrzynecki, and its first cabaret evening followed in December of that year. It became one of the best-known cabarets in postwar Poland, and a foundation has kept its archive and its programme going since 1998.

The Town Hall Tower dates from the 14th century and is the only part of the old town hall still standing: the rest was demolished in 1820 to open up the square. Look at it from a distance and you can see it leans a little. Its cellars once held the city prison. Today the tower is a branch of the Historical Museum of Kraków, and a climb to the top gives you the square laid out like a plan.

A fire in 1555 destroyed the Gothic Cloth Hall, and it was rebuilt in the Renaissance style. Traders still work under its arcades. The upper floor is a branch of the National Museum, with a gallery of 19th-century Polish art. Even a short pass through the central passage tells you why this was the commercial centre of the town.

The Rynek Underground opened in 2010 after archaeologists dug below the square from 2005 to 2010. Under glass walkways you pass the remains of merchants' stalls, old fortifications and the lines of earlier streets, with everyday objects and screens that show the market at work. It is a good place to see how the ground level of the town has risen over the centuries.

Small and set a little below the street, St Adalbert's church is Romanesque in origin and counts as the oldest stone building on the square. A Baroque phase in the 17th century gave it the green dome you can see from across the square. The Romanesque window in the east wall of the chancel is the sign of its early age.

The square looks like a single design, but this route shows that it has layers: a Romanesque church at the edge, a rebuilt trading hall, a surviving tower, stalls under the glass and a cabaret in the cellar. Come back once more in the evening, when the Cloth Hall is lit and the tower stands alone.