Digging for ... gin?

In the corner of the gin terrace there's a curious stone structure which we started using as a dumping space for garden waste as soon as we moved in.

Yesterday I started clearing it, whilst we've still got a skip on the drive. It's now down to good soil and a huge collection of beautiful river stones and a few good chunks of slate. 

There's more stones in there still and the soil will be moved onto the garden somewhere so we can see how the space might be usable - gin bar? Composting garden toilet?

It's the coolest spot in the garden because the sun doesn't get to it. It's also the coolest spot because it has the best view!