Before seeing Woodhenge, visitors to the area sometimes anticipate that it might partly resemble Stonehenge. But there is actually little of the original structure that can be easily noticed. Indeed little was seen until it was excavated early in the 20th century, after being identified largely from aerial photography.
The monument consists of an Outer Bank, an Inner Channel, and several Oval Rings of Holes. Most of the latter possibly held timbers, though some appear to have held stones. Concrete post are now cemented into the Holes, and this effectively indicates the arrangement of the Oval Rings.
There are various theories about possible structures that might have risen from the Oval Rings, and about how the axes, etc, of the Ovals might have aligned with positions of the Sun on the Skyline. But opportunities remain for further work in this respect.
See also: Cahokia