4. Palk Strait: This is a strait between India and Sri Lanka.
The Strait is 33 to 50 miles. It was photographed by Soichi Noguchi, Japanese Astronaut aboard International Space Station on Expedition 22/23.
According to Ramayan this was built by Lord Ram and his Vanar Sena to rescue Sita, from the Asura king Ravana.
Now India is in dilemma whether to preserve or destroy it for shipping purposes.