This temple, 2kms from Srirangam is dedicated to Lord Siva. It is also known as Jambukeswaram.
This is the Appu Sthalam among the Pancha Bootha Sthalams.
The others are -
Tiruvannamalai (Thejo sthalam - Fire)
Kanchipuram (Prithvi sthalam - Earth)
Kalahasti (Vayu sthalam - Air)
Chidambaram (Akasa sthalam - Space).

The Siva Lingam (Appu Lingam) under a holy Jambu tree is submerged in water from a subterranean spring.  There is another Lingam in the shrine.  Daily prayers & worship are offered to both Lingams. There is a separate shrine for the Goddess, Akhilandeswari facing east, while the Lord faces west.

The temple is situated amidst a mango grove. There are 7 gopurams and the temple is surrounded by 5 walls.  The sculptures & carvings are of the Chola period.  In a pillar in the Mahamandapa of Akhilandeswari temple, there is a magnifi ient figure of Ekapadeswarar, with Brahma & Vishnu on either side with their vahanas.

During the mid-day puja, the priest is dressed as a female while offering worship, signifying that Godddess Parvati herself is offering prayers to the Lord.

Legend
An elephant and a spider were offering worship to the Lingam simultaneously.  The spider would spin a web giving cover to the Lord.  The elephant would bring water in its trunk to do Abhishekam to the Lord.  He found the web in the way & destroyed it.  The spider spun the web again & the elephant destroyed.  This continued & one day the angered spider got into the elephants trunk to disturb him.  The elephant struck his trunk against a rock.  The Lord was pleased with their relentless devotion & both the spider and the elephant attained moksham.  Since an elephnat worshipped the Lord here, the place is known as Tiruvaanaikaaval (Aanai in Tamil-Elephant)

This place is also known as Jambukeswaram.  There was once a rishi who performed tapas in this region.  The Lord was pleased with his prayers & agreed to give darshan to devotees here as Jambukeswarar.