Photo: Ingo Mehling · CC BY-SA 4.0 · via Wikimedia Commons
Mud Flood · Kraków, Poland
Rynek Underground
The open question
The old market square is under the new one. When did the ground rise, and why?
On the record
A museum of about 4,000 m² under Kraków's main square, opened on 24 September 2010.

