When exploring the underground on Česká Street with a probe placed in front of the facade of a former perfume store named Convalaria, a small medieval cellar with an access corridor was discovered. A small well with brick timbering was found on the clay floor in the centre of the room under the dirt. Inside the well there was even a well-preserved pumping device.

The discovered late Gothic cellar was built approximately in the second half of the 15th century. The relatively small object is bricked in stone and mixed masonry and is roofed with a brick barrel vault. It is located less than two metres below street level, between two trees, directly in front of the glass window of what is now a café. The access corridor to the cellar from the south was probably connected to another cellar that disappeared with the construction of the present building. The cellar was probably used as a storage space, and later for access to the well. This is very unusual. From the level of the brick-paved floor, it is about 4 metres deep and is still active. Its timbering is interesting, which was lined with bricks, tiles, and stone. Its diameter changes from circular to square and again to circular with increasing depth.

The discovered cellar could not be connected to the existing building, so the entrance was set up on the opposite side. At the head of the Gothic wall an arched hole was connected to the newly established entrance shaft. The well was fitted with a lattice, and the found pump was handed over to the technical museum by archaeologists. Today, it is possible to enter the cellar only by a cast-iron hatch installed in the tiles. With the summer gardens of neighbouring restaurants in place, few people will notice this entrance.