THE PORTAL MONOLITH

The Portal Monolith is the largest stone (23-feet high, weighing about 50 tons) and is a unique element of STARHENGE. During the three months centered on the winter solstice, sunlight falling through the portal will cast an image that moves across the Vision Stone. During the three months of the year centered on the summer solstice, the full moon will take the same role, casting its image on the Vision Stone and allowing observers to track the 18.6-year cycle between major standstills.