Rio Guadalmina River Gorge Walk, Benahavis

So much fun, we did it twice! And it's completely free, unless you pay for a guided experience with an organised canyoning tour group: pro tip: you don't need to spend the money... just make sure you're wearing aqua shoes with good soles, or trainers you don't mind getting wet.
It can be very slippy underfoot with all the slime on the rocks. This could have been due to low water levels and a lot of sunshine, as there was no slime in the deeper, narrower, darker parts.