Head 14,000 feet up into the clouds on this hike, which is in Colorado. It’s one of the most treacherous hikes in the world and is a lengthy 13-miles. Rapidly changing weather conditions makes it incredibly dangerous. Additionally, the elevation gain exposes trekkers to potentially harmful altitude sickness. You’ll cross through three different ecosystems on the hike, with incredible sweeping views. It’s also known as the “most dangerous climb,” so beware if you do decide to embark on this adventure (Roots Rated).