According to legend, the Polish city of Kraków is built on the site of a dragon's lair. The dragon (Smok in Polish) lived in a cave beneath what is now Wawel Castle. Smok was a fairly typical dragon, breathing fire and subsisting on a diet of livestock and virgins, until he was finally defeated by a wily peasant who fed him a sheep stuffed with sulphur!
The image of the dinosaur track is taken from an episode of the documentary series Beast Legends, shown recently on the Canadian History channel. This particular episode dealt specifically with Smok... focusing not so much on the historical legends, as on the practicality of the dragon as a living organism!
[Thanks to Ewa Babarowski for drawing the Beast Legends documentary to my attention.]