And they have the bones to prove it.
In the early 14th century when the city of Kraków, Poland looked something like this, there lived an evil dragon named Smok Wawelski who terrorized the city.
The dragon* lived in a limestone cave hidden beneath the slopes of Wawel Hill, where the King's castle rested.
*Note the dragon pictured above is a Hungarian Horntail, not Smok. Unfortunately the GIF technology in 14th century Poland was not what it is today.