Henges are circular enclosures marked out by an earth bank and an inner ditch. They often have one or two entrances. Sometimes internal pits or circles of post-holes can be seen. They are most common in the south of England, but are known in the North. The northern examples tend to be smaller. They are often found associated with a range of other monuments including barrows and processional avenues. They date to the Bronze Age (2500BC to 800BC) and were probably used for religious or ceremonial purposes.