This is a consecrated linga of Shiva. You can make offerings and go close to the Deity. you can go and sit close. You can go to meditation states effortlessly.
How to get there
You can take a cab from any train station to the temple.
Map: https://goo.gl/maps/U22iHnKSmXsPkTQPA
About Walkeshwar Temple:
Walkeshwar Temple, also known as the Baan Ganga Temple, is a temple dedicated to Lord Shiva located in Walkeshwar, near Malabar Hill neighbourhood, in South Mumbai precinct of the city of Mumbai, India. It is situated at the highest point of the city,[1] and close to the temple lies the Banganga Tank.
Legend has it that Hindu god, Rama paused at that spot on his way from Ayodhya to Lanka in pursuit of the demon king, Ravana who had kidnapped his wife, Sita. Then Lord Rama was advised to worship Shiva lingam and he is said to have constructed the original linga of sand, after getting tired of waiting for his brother, Lakshman to bring an idol. The name is etymologically derived from the Sanskrit word for an idol made of sand — Valuka Iswar, an Avatar of Shiva.
As the story progresses, when Rama was thirsty, as there was no fresh water readily available (only sea water), he shot an arrow and brought Ganges over here. Hence Bana (arrow in Sanskrit) Ganges. The water that feeds the tank stems from an underground spring at that spot, despite its proximity to the sea.
Source:
https://en.wikipedia.org/wiki/Walkeshwar_Temple
