If you climb atop that large boulder , where the lighthouse is located, you can see the Mahabalipuram backwaters.This is locally called the Valayankuttai , literally the fisherman’s pond in the local parlance. Since this particular temple is located by the side of this lake, locals called it the Valayankuttai Ratha.
The temple is carved out of an isolated freestanding boulder. It is unfinished, though almost at the verge of completion. The reason why it was abandoned at this stage of completion will remain as a mystery, like many unanswered questions on Mahabalipuram. So is the patron of this temple, though some like to attribute it to Rajasimha (695 CE-728 CE) who also built the more famous Shore Temple.
From the town square take the Thirukalukundram road towards west. It's a 10minutes walk. You can also reach Valayankuttai Ratha from the Mahishamardini Cave, again a 10-15 minutes walk. Other attractions near to this are are the twin rathas called Pidari Rathas.
The unfinished Valayankuttai Ratha at Mahabalipuram.