Sri Sundararaja Perumal Temple (Nagapattinam)

The temple's deity carries the epithet "Kaveri Thuraivan" ("Lord of the Kaveri's shore"), named for the nearby Odambokki tributary of the Kaveri, also known locally as the Virutha Kaveri. Thirumangai Alvar sang ten pasurams in praise of this temple, part of his wider circuit of the Chola Nadu coast.

What sets Thirunagai apart from every other Divya Desam is that it is not really one shrine but three, gathered in a single temple complex: Vishnu is worshipped here standing as Sundararaja (also called Neelamegha Perumal), seated as Govindaraja, and reclining as Ranganatha, the only Divya Desam where a devotee can view all three classical postures of Vishnu icons under one roof in a single visit.

Present-day Nagapattinam is traditionally believed to have been a forest known as Sundararinyam, where the deity Dhruva performed penance to Vishnu during the Treta Yuga, giving the town its older name and its association with this Divya Desam.

The temple's construction is attributed to the Medieval Cholas of the late 8th century CE, with further contributions from the Pallavas and local Nagar merchant guilds through the 8th to 10th centuries. In later centuries, the Thanjavur Nayaks and, after them, the Thanjavur Marathas made significant additions, a Nayak-era king is credited with building the temple's seven-tiered tower, while a benefactor remembered locally as Jagul Nayakar is said to have added the tower, mandapams and the compound wall.

Beyond the unusual triple-posture arrangement of Sundararaja (standing), Govindaraja (seated) and Ranganatha (reclining), the temple holds a bronze image of Ashtabhuja Narasimha, an eight-armed form shown simultaneously blessing the child-devotee Prahlada with one hand and slaying the demon king Hiranyakashipu with another.

Being a coastal temple, the seven-tiered gopuram historically carried a lamp at its summit that is said to have served sailors as a navigational light for ships approaching or passing Nagapattinam's harbour, an unusual maritime role for a temple tower, tied to the town's long history as a port.

The temple's chariot festival (ther thiruvizha), held in the Tamil month of Chittirai (March–April), is its principal annual celebration. A ten-day festival in the month of Aadi marks the summer solstice, during which the processional deity is taken through the streets around the temple. The Saturdays of the month of Puratasi are also observed with particular devotion, with Perumal presented in a different divine ornamentation (alangaram) each week.

Daily worship follows the customary schedule of Chola Nadu Divya Desams, with separate rituals typically observed for each of the three sannidhis (Sundararaja, Govindaraja and Ranganatha) within the complex.