Srirangam Temple part 1

According to the temple's website, Srirangam can be considered the biggest functioning  temple in the world, as it covers an area of about 631,000 square metres (6,790,000 sq ft) with a perimeter of 4 km (10,710 ft).[1] Angkor Wat is bigger but non-functioning.

Srirangam is the foremost of the eight self-manifested shrines (Swayam Vyakta Kshetras) of Lord Vishnu. It is also considered the first, foremost and the most important of the 108 main Vishnu temples (Divyadesams). This temple is also known as Thiruvaranga Tirupati, Periyakoil, Bhoologa Vaikundam, Bhogamandabam. In the Vaishnava parlance the term "KOIL" signifies this temple only. The temple is enormous in size. The temple complex is 156 acres (0.63 km2) in extent. It has seven prakaras or enclosures. These enclosures are formed by thick and huge rampart walls which run round the sanctum. There are 21 magnificent towers in all prakaras providing a unique sight to any visitor. this temple lies on an islet formed by the twin rivers Cauvery and Coleroon.

The Srirangam temple complex is composed of 7 concentric walled sections and 21 towers gopuram. The gopuram of the temple is called the Rajagopuram and is 236 feet (72 m) tall, the tallest in Asia.