St. Leonard's Crypt under the Wawel Cathedral in Kraków, Poland, is a Romanesque crypt founded in the 11th century by Casimir I the Restorer who made Kraków his royal residence as the capital.
At the end of the 11th century construction work began on the cathedral called ‘Hermanowska’. It is probable that Władysław I Herman was its benefactor. The cathedral was consecrated in 1142. More is known about this new structure because its image is featured on a chapter house seal from the 13th century and its present-day remnants are well preserved – including the lower part of the Silver Bell Tower.
The entire St. Leonard's Crypt is supported by eight columns. In 1118 bishop Maurus was buried there.
Wikipedia https://en.wikipedia.org/wiki/St._Leonard's_Crypt
Address 5 Zamek Wawel, Kraków 31-001, Poland
Coordinates 50°3'17.506" N 19°56'8.12" E