L'isola del Gelato in Piazza Yenne in Cagliari is an ice-cream parlour built into the granite rock of the city, where there is a natural waterfall and well in the shop.
Oh and it has probably the best ice-cream in the city!
Here is a guided tour...

http://uk.youtube.com/watch?v=M5SmTggF2Dc&feature=related

i agree with you!!:D