For a great day out for all the family try a canoe trip down the Rio Sella from Arriondas or the Deva starting from Panes. Though passing through beautiful mountain scenery the rivers are quite tranquil in their lower stretches and the organisers have got it all thought out - you get a locker, a nice picnic, a water-proof canister for your bits and bobs, a canoe (obviously) and a lift back to the start point from wherever you end up. The Sella can get a bit busy in the peak season especially the first weekend in August when thousands of party people go down and celebrate the International Descent of the Rio Sella - to be avoided if it's tranquility you are looking for - the Deva is generally less frequented.