Slovenia, Skocjan caves area, camping
 

Camping signposted from the main dual carriageway, and from the caves, so you can't miss it.

Down a very steep hill and into a field, you can actually pitch your tent on the little island in the river if you want (and ride across the stream, or park the bike across the bridge, but beware of huge thunderstorms turning everything to slippery mud if you ride across!!).

Shady and peaceful and fantastic showers.