The entrance to the Underground Tourist Route is located in Rydzikowa tenement building from the beginning of the 17th century, it owes its name to the first owner – Wojciech Rydzik.
It is a classic example of the Jarosław type old tenement buildings. Under the tenement building, similarly to other buildings located in the Old Town, there are cellars, the so-called merchant warehouses, useful for commercial purposes. They were hollowed in loess the layer of which below the surface of the market square is around 30 m. They were used for storing goods imported for the famous Jarosław fairs.
The Rydzikowa old tenement building is now a private property. The Underground Tourist Route located underneath has a name of Prof. Feliks Zalewski, a scientist whose contribution during a rescue operation to the town endangered with a construction disaster was enormous. The route consists of the walkways and chambers adopted to sightseeing. It is 150-metre long, and the lowest tier is located at the level of ca 9 m. The Underground Tourist Route was put into service on June 1, 1984.
The memorial plaque located at the entrance to the Rydzikowa tenement depicting the character of Prof. Feliks Zalewski was made by the sculptor Stanisław Lenar. A painter and graphic designer – Edward Kieferling is the author of the illustrative boards and signboards, and ceramic elements located in the interior of the underground passages come from the resources of Jarosław High School of Arts.