The City of Dwarka
Claimed 3000+ BCE; structures dated 1500 BCE
In 2001, the National Institute of Ocean Technology discovered a submerged city in the Gulf of Khambhat off the coast of Gujarat, India, at a depth of 36 metres. Sonar imaging revealed geometric structures, walls, and what appear to be streets covering a 9-kilometre area. Carbon dating of recovered wood and artifacts suggested dates of up to 9,500 years ago — which would make it the oldest known city in the world by 5,000 years.