Mt. Makalu (8463 meters), fifth highest peak in the world, stands guard over the upper Barun Valley, and area of remarkable biological diversity and religious importance. Here lie Tibetan Buddhists’ legendary “hidden valleys,” caves with holy powers, and home of the Yeti. The trek begins with a flight to Tumlingtar, and spends the next week among village of Rai, Sherpa, and Bhotia peoples. Once inside Makalu-Barun National Park, the trail leaves civilization behind and winds upward through dense forests rimmed by soaring granite cliffs. From Shipton La and Barun La sweeping views of Mt. Everest, Makalu, and Kanchenjunga open up. Base camp touches the Barun glacier, inviting exploration among the towering peaks. The return route descends the gigantic Arun valley, a living museum of colorful birds, bamboo craftsmanship, and traditional lifestyles, ending back in Tumlingtar.