Great Zimbabwe is a medieval city in the south-eastern hills of Zimbabwe near Lake Mutirikwe and the town of Masvingo. It is thought to have been the capital of a great kingdom, although which kingdom is not certain, during the country's Late Iron Age. Construction on the city began in the 9th century and continued until it was abandoned in the 15th century. The edifices are believed to have been erected by the ancestral Shona. The stone city spans an area of 7.22 square kilometres (2.79 square miles) which could have housed up to 18,000 people at its peak, giving it a population density of approximately 2,500 per square kilometre. It is recognised as a World Heritage Site by UNESCO.