The main flow of tourism in Nepal with no doubt is trekking, started by early pioneer like Tony Hagen-Bill Tillman and Jimmy Roberts find new trekking routes around Himalaya as well trail to Tibet.
Slowly trekking started from mid 1950’s after the climb of Mt. Everest by legendry late Tenzing and Hillary 1n 29th May 1953, since then the trekking became popular along with mountaineering expeditions.
Since last 3-4 decades Nepal Himalaya has been a wonderland for adventurer as well to witness its rich old culture along with flora and fauna.
Trekking in Nepal where you can trek in the harmony of peaceful natural surrounding walking into deep verdant alpine forest of tall to bush rhododendron with pines-oaks-hemlock-spruce and fir tree lines.
In spring and summer trekking in Nepal will be magic with blooming wildflowers turning the hills and valley into riot of colors in the back drop of high snowcapped mountains.
http://teamhimalaya.com/teamhimalaya_blog/trekking-nepal-himalaya/