Attached to attractions or exhibits in museums, QR Codes provide a bridge to valuable information about the artworks.
Or on the back of a map, QR Codes can lead to detailed descriptions of places worth seeing.
Offering tourists the possibility to download a PDF (in their own language) with useful info is also an interesting use case. Documents can be constantly updated and improved. No animals will be harmed and no paper will be wasted.
Another cool thing about downloading a PDF is that once it is downloaded it stays in your phone and you can check it out even without 3G. This becomes an interesting feature when you have no roaming or (best case scenario) no signal. This will mean you are really on holidays :)