Mound 72 is a ridgetop mound, one of only six recorded at the Cahokia site.Unlike the other ridgetop mounds which are aligned east/west and north/south (as are most other features at the large site), Mound 72 is aligned 30 degrees off the east/west line.Over this first phase a 46 feet (14 m) square platform with two levels and ramp on its eastern side was constructed.
This mound was constructed precisely over the remains of a dismantled charnel house that was thought to have been erected at roughly the same time as the woodhenge post which it is next to.
Interred in the mound were 2 recently deceased men and several bundled burials, probably the previous residents of the charnel house who had waited for the elite personages to die in order to be interred with them.
This burial is now known as the "Beaded burial" or the "Birdman burial".
Below the birdman was another man, buried facing downward.
Early in the history of Cahokia the portion of the site containing Mounds 72 and 96 was the location of a "woodhenge", a ceremonial area with a 412 feet (126 m) in diameter circle of 48 upright wooden posts.
Archaeological research has shown that four of the posts were at the cardinal locations of north, south, east and west, the eastern and western posts marking the position of the equinox sunrise and sunsets.
Mound 72 is a small ridgetop mound located roughly 850 meters (2,790 ft) to the south of Monks Mound at Cahokia Mounds near Collinsville, Illinois.
Early in the site's history, the location began as a circle of 48 large wooden posts known as a "woodhenge".
A large rectangular pit was dug into the southeast corner of the mound and a mass burial of 24 women was made in it.
A new layer of fill was added to the mound and it was extended to the southeast toward Mound 72sub1, for a ramp or extension over the mass burial.
This alignment is the same as the summer solstice sunrise/winter solstice sunset line for this latitude.