Treks in Nepal follow the long established trails between villages and ancient trading routes over Himalayan passes. The three main trekking areas and therefore the most easily accessible are the Everest, Langtang and the Annapurna regions. Annapurna and Langtang have a slight advantage in so much that they can be reached via road connections. Trekkers are of course rewarded when they venture further afield as well! Great Himalaya Trails has extensive information on other trekking regions, which are accessible by domestic flights, such as Kanchenjunga, Makalu, Dolpo, and the Far West. Several days of trekking is required to reach the higher mountain areas from the local centers of population and administration.