Beneath the Market Square lies a remarkable subterranean museum excavated during renovation work in 2005-2010. The Rynek Underground follows the medieval street plan of the market at a depth of several metres, passing through the remains of market stalls, streets, and drainage systems that were buried by centuries of successive building phases above ground. The museum covers Krakow's history from its earliest settlements to the medieval commercial peak.
The display uses holographic projections, reconstructed merchant stalls, and interactive elements to bring the medieval market back to life. The experience is both informative and atmospheric — the low brick vaults and dramatic lighting give the underground spaces an otherworldly quality. Queues can be long in summer; booking online in advance is strongly recommended. The museum entrance is beneath the Cloth Hall.