At one of the places in India, if you stand on the seashore and watch the sea, you will find that the sea water recedes from the shore line a few kilometres and comes back to the shore, twice a day, and you can actually walk on the sea floor when the water recedes. This unique phenomenon is seen at

1. The question describes a unique phenomenon where the sea water recedes significantly from the shore line twice a day, exposing the sea floor for people to walk on. 2. This characteristic is famously associated with Chandipur beach in Odisha, often called the 'vanishing sea'. During low tide, the sea recedes for several kilometres due to the extremely shallow and wide intertidal zone. 3. Bhavnagar in Gujarat is known for its high tidal range, but the description of the sea receding several kilometres allowing people to walk is most specifically attributed to Chandipur. 4. Bheemunipatnam and Nagapattinam are coastal locations but are not known for this specific, dramatic tidal recession phenomenon. 5. Therefore, the location described is Chandipur.