Nature is the only thing that pleased every one. It's eye catching scenes, attractive beauty, delicious voices of birds and rivers gives a cool impact to some one's heart. That's why whenever we consider a soothing effect, nature and its beauty always glimpses on our mind.
Depending upon the personality some likes birds, few loves mountains others like river flowing. Similarly when talking about as a desktop wallpaper we again can't miss nature as it sometimes played a role of calming and relaxation training.