St. Florian's Gate was just 1/2 block from our hotel in Krakow. The permit to build it was issued in 1285. It was part of the medieval city walls. Here's the wikipedia article and here's my picture of the gate.
Just north of the gate is the Barbican of Krakow, built around 1498. Here's the wikipedia article on it and here's my picture.
If you zoom out 3 clicks, you can see the park area that was built where the old wall was torn down.