Construction starting in the 11th century and continuing for over 300 years, the ruins at Great Zimbabwe are some of the oldest and largest structures located in Southern Africa. At its peak, estimates are that the ruins of Great Zimbabwe had as many as 18,000 inhabitants. The ruins that survive are built entirely of stone. The ruins span 1,800 acres (7 km²) and cover a radius of 100 to 200 miles (160 to 320 km).
The ruins can be broken down into three distinct architectural groups. They are known as the Hill Complex, the Valley Complex and the famous Great Enclosure. The Hill Complex was used as a temple, the Valley complex was for the citizens, and the Great Enclosure was used by the king. Over 300 structures have been found so far in the Great Enclosure. The type of stone structures found on the site gives an indication of the status of the citizenry. Structures that were more elaborate were probably built for the kings and situated further away from the centre of the city. It is thought that this was done in order to escape sleeping sickness.
What little evidence exists suggests that Great Zimbabwe also became a centre for trading, with artefacts suggesting that the city formed part of a trade network extending as far as China. Chinese pottery shards, coins from Arabia, glass beads and other non-local items have been excavated at Zimbabwe. Nobody knows for sure why the site was eventually abandoned. Perhaps it was due to drought, perhaps due to disease or it simply could be that the decline in the gold trade forced the people who inhabited Great Zimbabwe to look for greener pastures.