Open steppe and emerald meadows. Forested valleys and thick marshland. Turquoise alpine lakes and glaciated peaks. Western Mongolia's 2,456-square-mile Altai Tavan Bogd National Park, in the Altai-Sayan eco-region, near the Chinese border, has it all. Explore the park on Tusker Trail's 15-day, 100-mile Mongolia Trek—16 guests, six camels, a local guide, and a cook cover eight to ten jaw-dropping miles per day by foot and horseback, traversing around the Five Holy Peaks of Altai and keeping eyes peeled for argali, lynx, and Saker falcons. Digs are sturdy mountain tents, as well as the ger camps of nomadic Kazakhs on days two and 12. If you're lucky, your hosts may show you a thing or two about their 1,000-year-old tradition of hunting with golden eagles. $5,140; tusker.com.