Dwellings in the 2nd millennium BC were very similar to those in the Neolithic period. The most common constructions were circular or elliptical huts built individually though possibly grouped together. There were villages, but there was no concept of urban organisation as the dwellings were randomly sited. In 1300 BC, villages consisting of adjoining rectangular houses built alongside thoroughfares and around squares began to appear. Throughout the 7th and 6th centuries BC, urban nuclei grew more complex and often had defensive walls surrounding them. Cremation burial customs also began to spread.