Bighorn Medicine Wheel

On top of the Bighorn Range in Wyoming, a desolate 9,642 feet high and only reachable during the warm summer months, lies an ancient Native American construction -- an 80' diameter wheel-like pattern made of stones. At the center of the circle is a doughnut-shaped pile of stones, a cairn, connected to the rim by 28 spoke-like lines of stones. Six more stone cairns are arranged around the circle, most large enough to hold a sitting human. The central cairn is about 12 feet in diameter and 2' high.

If you stand or sit at one cairn looking towards another, you will be pointed to certain places on the distant horizon. These points indicate where the Sun rises or sets on summer solstice and where certain important stars rise heliacally, that is, first rise at dawn after being behind the Sun. The dawn stars helped foretell when the Sun ceremonial days would be coming. The area is free of snow only for 2 months -- around the summer solstice.

solar-center.stanford.edu/AO/bighorn.html