This is Angel's Landing in Zion National Park, southern Utah. Looking closely on the right you can see the trail as it winds up to the top, 1565 feet above the canyon floor. Yeah, this is a webshot, but I wanted you to see it for the scale of what you'll see under the cut.
A few years ago, my sister, her son, and I took a trip there and hiked to the top. The first pic you'll see is my nephew Chris looking into the valley from above the sheer rock face on the webshot. The second pic is me, looking down into the valley a little below where Chris was. That sheer face is a favorite for rock climbers, and a group was about 1/2 way up setting up "camp." They clipped themselves into hammocks suspended about 1000 feet up or so and spent the night. I want to DO that someday.