From May to early July, the haymeadows of the Picos de Europa are simply glorious: some of the richest temperate grasslands in the world, literally teeming with orchids and butterflies. Add to this the faunal and floral delights of the alpine rockgardens and the diversity of woodland types in the surrounding valleys - ranging from Mediterranean evergreen forests to cool, humid swathes of beech and sessile oak, from mixed deciduous canopies of ash, wych elm and small-leaved lime to extensive tracts of Pyrenean oak - and you have the recipe for the perfect natural history holiday.