Henge
There are three related types of Neolithic earthwork that are all sometimes loosely called henges. The essential characteristic of all three types is that they feature a ring bank and ditch, but with the ditch inside the bank rather than outside. Due to the poor defensive utility of an enclosure with an external bank and an internal ditch, henges are not considered to have served a defensive purpose (cf. circular rampart). The three types are as follows, with the figure in brackets being the approximate diameter of the central flat area: