One of the world's most spectacular mass migrations takes place every year at the Gahirmatha Beach in Odisha. Every year starting in November, there is huge migration of Olive Ridley Sea turtles to this beach, for mating and nesting, where they lay their eggs. This is the only beach in India, where this occurs, and it is estimated that the nesting figure, could be as large as 500,00 though of late, there has been a decline due to rampant poaching, and attacks from predators like dogs, sea gulls. The turtles travel all the way from Sri Lankan coast to the beach, where they indulge in mass mating and courtship, after which the eggs are laid. Holes are dug in the sand, by the turtles themselves using their flippers, to a depth of 45 cm and lay between 100-180 eggs at a time. After 50-60 days, the eggs are hatched, and the hatchlings make it back to sea, one of the most spectacular sights, watching the tiny ones reaching the sea en masse. It is also the time, when predators, attack the tiny hatchlings, and it's estimated only 1 in a 1000 survives.
Chandipur
Another unique natural phenomena, at the Chandipur Beach, when the sea tide recedes during low tide, about 1 to 4 km. You can literally walk into the sea during that time.
Loktak Lake
Loktak Lake in Manipur, is noted for it's phumdis or floating islands, which are basically masses of vegetation and soil. The largest of these Phumdis in South East of lake, makes up the famed Keibul Lamjao National Park, the world's only floating park.