Sun Dagger at Winter Solstice
Sun Dagger at Summer Solstice
Fajada Butte
Fajada Butte, at the eastern end of Chaco Canyon.  Home to petroglyphs which might have astronomical alignments.  There is speculation that alignments influenced the location of the structures of Chaco Canyon.
The Chaco Canyon Sun Dagger is the most famous of the petroglyphs found on Fajada Butte.  Unique amongst solar markers in that it works at noon thanks to the three stones shown below.  .
1