The royal castle on Wawel Hill was the seat of Poland's kings for many centuries. This 16th century Renaissance courtyard is one of the highlights, although some of the interiors are spectacular as well.
We visited Krakow in 2004 with my parents and kids, and this is where I first started shooting collections of mutually visible panoramas. You might say that this was the world's first proto-synth. :-)
Note that the shots under the arcade don't currently synth together with the rest of the photos.