Adam's Bridge, also known as Rama's Bridge or Rama Setu, is a chain of natural limestone shoals, between Pamban Island, also known as Rameswaram Island, off the south-eastern coast of Tamil Nadu, India, and Mannar Island, off the north-western coast of Sri Lanka. Geological evidence suggests that this bridge is a former land connection between India and Sri Lanka.
The feature is 48 km (30 mi) long and separates the Gulf of Mannar (southwest) from the Palk Strait (northeast). Some of the regions are dry, and the sea in the area rarely exceeds 1 meter (3 ft) in depth, thus hindering navigation. It was reportedly passable on foot until the 15th century when storms deepened the channel. Ramanathaswamy Temple records say that Adam's Bridge was entirely above sea level until it broke in a cyclone in 1480.
The Marine and Water Resources Group of the Space Applications Centre (SAC) of the Indian Space Research Organization (ISRO) concludes that Adam's Bridge comprises 103 small patch reefs.