Wikipedia
Sthalasayana Perumal Temple (also called Thirukadalmallai) is at Mahabalipuram. Constructed in the Dravidian style of architecture, the temple is glorified in the Divya Prabandha, the early medieval Tamil canon of the Azhwar saints from the 6th–9th centuries AD. It is one of the 108 Divyadesam dedicated to Vishnu, who is worshipped as Sthalasayana Perumal and his consort Lakshmi as Nilamangai Thayar. The temple is believed to have been built by Pallavas, with later contributions from Medieval Cholas, Vijayanagar kings and Madurai Nayaks.
The temple is believed to be the birthplace of the Vaishnava Azhwar saint Bhoothathalvar. Sthalasayana Perumal is believed to have appeared to sage Pundarika. The temple is open from 6 am to 12 pm and 3pm to 8:30 pm and Six daily rituals and a dozen yearly festivals are held at the temple, of which the Bhoothatazhwar Avata festival, celebrated during the Tamil month of Aipasi (October–November) being the most prominent. The temple is one of the 32 Group of Monuments at Mahabalipuram that are declared as UN world heritage sites, but unlike others that are maintained by the Archaeological Survey of India, the temple is maintained and administered by the Hindu Religious and Endowment Board of the Government of Tamil Nadu.