One of the best ways to see the world is by looking down from above, and these high-altitude destinations give access to some of the most jaw-dropping vantage points on Earth. In addition to breathtaking natural vistas and challenging terrain, all of these routes offer stylish lodges that provide a pampering home base and fascinating cultural excursions that can be combined with outdoor activities to create a robust itinerary. For adventurous and in-the-know travelers looking for walks filled wi...