Dvaraka, popularly known as Dwarka, possibly meaning having many gates, or alternatively having one or several very grand gates. It is a sacred historic city in Hinduism, Jainism, and Buddhism. The name Dvaraka is said to have been given to the place by Lord Krishna, a major deity in Hinduism. The following description of Dvaraka during Lord Krishna’s presence there appears in the Bhagavata Purana (Srimad-Bhagavatam; 10.69.1-12) in connection with the sage Narada’s visit. It is also mentioned in the ancient prehistoric epic period of the Mahabharata. According to legend, Lord Krishna settled here after he defeated and killed his uncle Kansa at Mathura.
Dwaraka is one of the Sapta Puri of Hinduism. The Sapta Puri are seven holy pilgrimage centres in India which are: Ayodhya (Lord Vishnu as Rama), Mathura (Lord Vishnu as Krishna), Haridwar (Lord Shiva as Gangadhara), Varanasi (Lord Shiva as Vishwanath), Kanchipuram (Lordess Durga as Kamakshi), Ujjain (Lord Shiva as Mahakaleshwar) and Dwarka (Lord Vishnu as Krishna).
According Harivamsa, Dvaraka is described as largely built on "submerged land", "released by the ocean". Nearby was the mountain range Raivataka, "the living place of the gods". It had surrounding walls with four main gates. Its houses were arranged in lines and the city had high buildings made in gold, which almost touched the sky and could be seen everywhere like clouds. It had a temple area with a palace for Lord Krishna himself, which had a separate bathroom. It was a very rich city and the only city on earth which was studded with gems.
During 1983-1990, the Marine Archaeology Unit of India's National Institute of Oceanography (NIO) carried out underwater excavations at Dwarka and Bet Dwarka. According to S. R. Rao "The available archaeological evidence from onshore and offshore excavations confirms the existence of a city-state with a couple of satellite towns in 1500 B.C." He considered it reasonable to conclude that this submerged city is the Dvaraka as described in the Mahabharata.
Below is the documentary links, both made on "Dvaraka / Dwarka city. One by Ancient Explorer, Amish Shah who travels to the west coast of India in search of an ancient submerged city. With a passion for the truth, he stumbles into a cover up and in this film, he goes public with what he found. Another one is made History TV channel.
Information Source Link and Youtube.