Saranatha — Vishnu the shelter-giver
The 108 Divya Desams are the sacred abodes of Vishnu sung by the 12 Alvar saint-poets. Compiled as the Nalayira Divya Prabandham by Nathamuni (9th c. CE), this corpus of 4,000 pasurams defines the sacred geography of Tamil Vaishnavism and the Sri Vaishnava sampradaya.
The only Divya Desam where five different Vishnu-forms share the same sanctum — worshipped together at one circumambulation. Said to be Kaveri's wedding gift from Vishnu.
Daily 5-fold puja; Vaikuntha Ekadashi (Margazhi full moon) is the holiest day — the Paramapada-vasal gate is opened; passing through is said to grant moksha. Annual Brahmotsavam (10 days) features Vishnu on all his vahanas (Garuda, Hanumanta, Shesha, Hamsa, Simha, Ratha).
Each Divya Desam's sanctity rests on how many Alvars sang of it and how many pasurams — this is the mangalashasanam. Tamil Vaishnavism treats the 4,000 pasurams as Dravida Veda — equivalent to the Sanskrit Vedas.