The western and eastern borders to the north of Nepal are highly preserved region and were only opened for trekking since early 90s. The western border lies in the rain shadow area behind the Himalayan chain and are usually arid, dry and high that extends to Tibetan plateau.
ABC Trek is known as Annapurna Sanctuary Trek or Annapurna Base Camp Trek and it is most famous trekking journey in the Annapurna Region of Nepal through Pokhara city.