Explanation : Lothal, located along the Bhogava river, a tributary of Sabarmati, in the Gulf of Khambat in Gujarat, was the only port town of the Indus Valley Civilization. It had a basin with a vertical wall, inlet and outlet channels which has been identified as a tidal dockyard. Lothal's dock was the earliest known dock found in the world, equipped to berth and service ships. ....Read more