Adam's Bridge (Tamil: ஆதாம் பாலம்), also known as Rama's Bridge or Rama Setu or Ramsethu, is a chain of limestone shoals, between Pamban Island, also known as Rameswaram Island, off the southeastern coast of Tamil Nadu, India, and Mannar Island, off the northwestern coast of Sri Lanka. Geological evidence suggests that this bridge is a former land connection between India and Sri Lanka. The bridge is 18 miles (30 km) long and separates the Gulf of Mannar (southwest) from the Palk Strait (northeast). Some of the sandbanks are dry and the sea in the area is very shallow, being only 3 ft to 30 ft (1 m to 10 m) deep in places, which hinders navigation. It was reportedly passable on foot up to the 15th century until storms deepened the channel: temple records seem to say that Rama’s Bridge was completely above sea level until it broke in a cyclone in 1480.
Palk Strait (Tamil:பாக் சலசந்தி) is a strait between the Tamil Nadu state of India and the Mannar district of the Northern Province of the island nation of Sri Lanka. It connects the Bay of Bengal in the northeast with the Palk Bay and thence with the Gulf of Mannar in the southwest. The strait is 33 to 50 miles (53 to 80 km) wide. Several rivers flow into it, including the Vaigai River of Tamil Nadu. The strait is named after Robert Palk, who was a governor of Madras Presidency (1755-1763) during the Company Raj period. It is studded at its southern end with a chain of low islands and reef shoals that are collectively called Adam's Bridge.
Palk Strait Crossings
1954: Murugapillai Navratnaswami (or spelled Murugupillai Navaratnasamy) was the first person to cross the Palk Strait. His 59 km (36.7-mile) swim took 26 hours 50 minutes from Valvettithurai (VVT), Sri Lanka to Point Calimere, India on his second attempt.
1974: V.S. Kumar Anandan completed an unprecedented two-way crossing of the Palk Strait from Valvettithurai, Sri Lanka to Dhanushkodi, Tamil Nadu, India and then back to Talaimannar in a 51 hour swim.
2012: S.P. Murleedharan crossed the Palk Strait from Talaimannar, Sri Lanka to Arichamunai, Dhanushkodi, India in 13 hours 53 minutes. "As an Indian I feel proud to cross Palk Strait from Sri Lanka to India. The conditions were extremely tough for swimming. The sea, pleasant in the initial stage, turned very rough. It forced me to swim against the strong wind and choppy sea."
Unknown date: C.P. Saravanavadivu