Apart from Valmiki Ramayana, Ram Setu is mentioned in several ancient Hindu scriptures like Vedas, Puranas, epics, literature etc. Among the prominent scriptures mentioning Ram Setu are Yajur Veda (यजुर्वेद), Skanda Puran (स्कन्द पुराण), Vishnu Puran (विष्णु पुराण), Agni Puran (अग्नि पुराण), Brahma Puran (ब्रह्म पुराण), Mahabharat (महाभारत) and Raghuvansham (रघुवंशम) of Kalidas. For the Hindus, the Ram - Ravan struggle was real and historical, though the events belong to the immemorial past; but the modern historians of twentieth century described Ram as mythological figure and the ocean bridge as nature’s creation.
Presently, the recent evidences and researches have proved that the ‘setu’ is man-made. Several satellite images from various space agencies like NASA & ISRO etc portray a forty eight kilometer long land mass in the sea between Dhanushkodi in the south of India and Pamban in the northwest of Sri Lanka. The ‘setu’ is made of seven thousand years old rocks, placed on four thousand years old sand-bed. This discrepancy in the ages of the rocks and sand suggests that the bridge must have been built by the humans. The stones employed to construct the ‘setu’ have property to float in the water. It is being conjectured by the archaeologists that these are volcano stones. The Ramayana elucidates that Ram was engraved / written on every stone by the Vanar Sena (वानर सेना) before it was put into the sea; and this made those stones unsinkable, kept them floating.
Lord Ram had identified the beginning point of the bridge. The place where Lord Ram shot the bow is called 'Dhanushkodi' (धनुष्कोड़ी). Thereafter, he handed over the responsibility of building a bridge across the ocean to connect mainland India with Sri Lanka to Nal & Neel, the sons of Vishwakarma. As per Valmiki Ramayan, the bridge was built in about five days. Lord Ram termed the bridge as ‘Nal Setu’ (नल सेतु) because the technology to build it was provided by Nal.
There are several evidences in Valmiki Ramayan pertaining to sophisticated technologies used in making the bridge. Heavy stones were brought to the beach with the help of machines. Some army members (monkeys) were holding several ‘yojan’ (yojan – योजन = 4 Miles) long thread / rope, indicating the bridge was being constructed in a particular shape from Dhanushkodi to Pamban. Also, Dhanushkodi is the only site between India and Sri Lanka, where the sea is as deep as the river with land being occasionally visible. The sea around Ram Setu is very shallow, ranging from three feet to thirty feet deep. The ‘setu’ was entirely above sea level till 1480 AD but was damaged by a cyclone that hit the area. Over the centuries, the sea level increased and the bridge got submerged into it.