Built by a Native American Culture or a migrant European population? No one knows for sure. A maze of man-made chambers, walls and ceremonial meeting places, America's Stonehenge is debatably the oldest man-made construction in the United States (possibly over 4000 years old). Like Stonehenge in England, America's Stonehenge was built by people well versed in astronomy and stone construction. It has been determined that the site is an accurate astronomical calendar. It was, and still can be, used to determine specific solar and lunar events of the year. Students also enjoyed the company of alpacas up close and personal.