Mohenjo-Daro, Pakistan
One of the largest cities in the Indus-Valley region, as well as being one of the oldest cities in the world, Mohenjo-Daro was built around 2600BC with dwellings constructed from baked clay bricks giving it a unique style. Spread over a staggering 500,000 square kilometres, the site was initially occupied by farmers and later became a large trading city. Likely to have been a political base of the Indus Valley region, the city was laid out in a grid-pattern and had public areas such as baths and halls. The city also boasted excellent defences, despite lacking a city wall. Instead, towers and fortifications protected the city from threats. The city fell into ruins in 1900BC, although archaeologists have not been able to clarify why - theories centre around possible invasions, natural disasters or the citizens simply moving away as the river gradually shifted its path away from the city.
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