Mount Lemmon is a "sky island," which means that the top of the mountain is home to a verdant landscape filled with aspen trees, alpine meadows, and towering pines. But when you begin your hike on the lower flanks of the mountain, you'll be hiking through the land of cacti, rattlesnakes, and desert sand. Eventually you'll reach the cooler altitudes as you ascend the mountain. "While Lemmon’s heights have much of the same vegetation and wildlife as other high mountains in southern Arizona, these areas are isolated from each other by the desert in between – hence the term," explains Andinstaloco on SummitPost.org.

There are several different ways to reach the summit of Mount Lemmon, including driving up a highway. There's also an expansive trail system lacing the flanks of the mountain, with multiple hike options that could bring you to the peak. But if you're looking for a truly epic endeavor, consider backpacking from the base of the mountain to the summit and back down on this 41-mile round-trip hike.

Over the course of this route, you'll climb (and descend) a staggering 10,269 feet of elevation. While many potential routes to the summit exist, the one shown here traverses some of the more well-used trails and begins from the popular Sabino Canyon hiking area. This is an ambitious route that's intended for backpackers and peak climbers who are in search of a real challenge.