This is the Monument Valley in the Navajo Indian land, on the border between Arizona and Utah. One of the most impressive places I've ever seen.

If you go there (and everyone should, at least once in a lifetime), plan on spending at least a full day, or better two, with fewer vistors and better picture-taking conditions early in the morning or late afternoon.

And yes, hire a Navajo guide with a jeep; you will see more.

Clicking on any of the thumbnails will bring up a larger (900x600) version of the same image, 120-200kB in size.