Down in the desert, the 1.5-mile Santa Elena Canyon Trail, 40 miles southwest of Panther Junction, is one of the most popular treks in Big Bend because of the stunning rock and river views. It's rated easy, but you have to wade through a stream and climb stairs in the canyon wall. The adventurous (and ecoconscious) might seek out the trail that's left off maps. Hint: there are falls and lots of vegetation for the desert.